UBC Theses and Dissertations

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UBC Theses and Dissertations

An evaluation of noise barriers designed for truck traffic Jenkins, Robert Andrew 1977

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AN EVALUATION OF NOISE BARRIERS DESIGNED FOR TRUCK TRAFFIC by ROBERT ANDREW JENKINS B.A., U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1975 A THESIS SUBMITTED IN PARTIAL FULFULLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS i n THE FACULTY OF GRADUATE STUDIES SCHOOL OF COMMUNITY AND REGIONAL PLANNING We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA O c t o b e r , 1977 (E> R o b e r t Andrew J e n k i n s , 1977 In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h Co lumb ia , I a g ree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s tudy . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y purposes may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . It i s u n d e r s t o o d tha t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i thou t my w r i t t e n p e r m i s s i o n . School fiep-a-rtmen-t of Community and Regional Planning The U n i v e r s i t y o f B r i t i s h Co lumbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date O c t o b e r 1» !977 i i . ABSTRACT R e c e n t l y a t t e n t i o n has been d i r e c t e d towards n o i s e r e s u l t i n g f r o m t r a f f i c on a r t e r i a l s , e s p e c i a l l y t h o s e a r t e r i a l s c a r r y i n g h i g h volumes o f t r u c k t r a f f i c . T h i s t h e s i s a d d r e s s e s t h e q u e s t i o n , "Are t h e r e t r a f f i c n o i s e b a r r i e r d e s i g n s w h i c h reduce n o i s e e f f e c t i v e l y when employed on a r t e r i a l s c a r r y i n g h i g h volumes o f t r u c k t r a f f i c ? " . C r i t e r i a f o r e v a l u a t i n g b a r r i e r s a re d e r i v e d f r o m e x i s t i n g r e s e a r c h and a r e t h e f o l l o w i n g : 1. N o i s e a t t e n u a t i o n e f f e c t i v e n e s s . 2. A e s t h e t i c i m p a c t . 3. C i r c u l a t i o n e f f e c t i v e n e s s ( p e d e s t r i a n and v e h i c u l a r ) . 4. C o s t . N o i s e a t t e n u a t i o n e f f e c t i v e n e s s i s d e a l t w i t h more e x t e n s i v e l y than the o t h e r c r i t e r i a . A n o i s e p r e d i c t i o n method i s s e l e c t e d f r o m t h r e e methods used i n r e c e n t t r a f f i c n o i s e r e s e a r c h . The c r i t e r i a f o r s e l e c t i o n o f t h e O n t a r i o N o i s e P r e d i c t i o n Method a r e b a s e d on i t s c o m p a r a t i v e : 1. A c c u r a c y ; 2. Comprehensiveness ( c a p a b i l i t y t o d e a l w i t h d i v e r s e t r a f f i c s i t u a t i o n s s u c h as low t r a f f i c volumes, t r u c k t r a f f i c and b a r r i e r c o n f i g u r a t i o n s ) ; 3. S i m p l i c i t y o f a p p l i c a t i o n . T a r g e t n o i s e l e v e l s t a n d a r d s a r e d e v e l o p e d c o n s i d e r i n g b o t h ambient n o i s e l e v e l s and speech i n t e r f e r e n c e c r i t e r i a . F i v e d e s i g n a r c h e t y p e s b a s e d on e x i s t i n g r e s e a r c h a r e i n t r o d u c e d . These d e s i g n s i n v o l v e l o w e r e d roadbeds, berms ( e a r t h mounds), and c o m b i n a t i o n s o f t h e s e s t r u c t u r e s . The a r c h e t y p e s a r e e v a l u a t e d w i t h r e s p e c t t o a case s t u d y s i t u a t i o n i n v o l v i n g t h e p o t e n t i a l c o n f l i c t between t r u c k t r a f f i c from t h e C o q u i t l a m R i v e r a r e a and t h e p r o p o s e d C o q u i t l a m Town C e n t r e l o c a t e d i n t h e Lower F r a s e r V a l l e y R e g i o n o f B r i t i s h i i i . C o l u m b ia. I m p o r t a n t i n the case s t u d y i s c o n s i d e r a t i o n o f f u t u r e t r u c k and a u t o volumes w h i c h w i l l g e n e r a t e t h e n o i s e and c o n s i d e r a t i o n o f the l a n d use t y p e s b o r d e r i n g the r o u t e . D i f f e r e n t t a r g e t n o i s e l e v e l s are s u g g e s t e d f o r d i f f e r e n t l a n d use t y p e s . Each o f t h e a r c h e t y p e s p l u s a c o n t r o l s i t u a t i o n (no n o i s e b a r r i e r ) a r e e v a l u a t e d w i t h r e s p e c t t o t h e c r i t e r i a o f n o i s e a t t e n u a t i o n e f f e c t i v e n e s s , a e s t h e t i c i m p a c t , c i r c u l a t i o n e f f e c t i v e n e s s and c o s t . C o n c l u s i o n s and recommendations r e s u l t r e g a r d i n g t h e e f f e c t i v e n e s s o f t h e a r c h e t y p e s . E m p l o y i n g the O n t a r i o N o i s e P r e d i c t i o n Method appears t o be a s u c c e s s f u l means o f e v a l u a t i n g b a r r i e r n o i s e a t t e n u a t i o n e f f e c t i v e n e s s . A l l b a r r i e r d e s i g n s a r e c o n s i d e r a b l y more d e s i r a b l e w i t h r e s p e c t t o t a r g e t n o i s e l e v e l s than t h e c o n t r o l s i t u a t i o n . However, d e s i r a b l e r e d u c t i o n s i n n o i s e a r e o n l y r e a l i z e d a t e l e v a t i o n s l o w e r t h a n 40 f e e t above ground as n o i s e shadows c r e a t e d by the b a r r i e r c o n f i g u r a t i o n s do n o t e x t e n d above t h i s h e i g h t . The d e s i g n s w h i c h a r e most e x p e n s i v e from a c o n s t r u c t i o n s t a n d p o i n t e n t a i l t h e w i d e s t r i g h t o f way w i d t h . I f t h e p u r c h a s e o f l a n d i s c o n s i d e r e d i n a t o t a l c o s t t h e e x t r a l a n d c o s t s c o u l d o v e r r i d e t h e cheaper c o n s t r u c t i o n c o s t s . The d e s i g n s a r e comparable f r o m a c i r c u l a t i o n s t a n d p o i n t b u t the berm d e s i g n s emerge as more a e s t h e t i c a l l y e f f e c t i v e . E m p l o y i n g t h e method-o l o g y s u g g e s t e d i n t h e t h e s i s (and o u t l i n e d h e r e ) c o n s t i t u t e s an e f f e c t i v e means o f e v a l u a t i n g t r a f f i c n o i s e b a r r i e r s . i v . TABLE OF CONTENTS PAGE ABSTRACT i i TABLE OF CONTENTS i v LIST OF TABLES v i LIST OF FIGURES v i i CHAPTER 1: INTRODUCTION AND METHODOLOGY 1 1.1 INTRODUCTION 1 1.2 METHODOLOGY 5 CHAPTER 2: ANALYSIS OF NOISE MEASUREMENT 13. 2.1 THE MEASUREMENT OF NOISE 13. 2.2 SELECTION OF THE NOISE PREDICTION MODEL 14. 2.3 SELECTION OF APPROPRIATE STANDARDS FOR NOISE LEVELS 17. CHAPTER 3: DESCRIPTIONS OF THE ARCHETYPES AND THE CASE STUDY 28. 3.1 DESCRIPTION OF THE CONTROL AND FIVE ARCHETYPES 28. 3.2 DESCRIPTION OF THE CASE STUDY 34. CHAPTER 4: NOISE ATTENUATION EFFECT OF THE FIVE ARCHETYPES 44. 4.1 INTRODUCTION 44. 4.2 APPLICATION OF THE ONTARIO NOISE PREDICTION MODEL 46. 4.3 COMPARISON OF THE EFFECT OF BARRIERS TO TARGET STANDARDS 52. CHAPTER 5: EVALUATION OF THE ARCHETYPES WITH RESPECT TO AESTHETICS AND CIRCULATION 58. 5.1 INTRODUCTION 58. 5.2 AESTHETIC EVALUATION 58. 5.3 CIRCULATION EVALUATION 62. V . PAGE CHAPTER 6: COST EVALUATION OF THE ARCHETYPES 67. 6.1 INTRODUCTION 67. 6.2 COMPARATIVE COST OF THE CONTROL AND FIVE ARCHETYPES 70. 6.3 ARE THE ARCHETYPES WORTH IT OR CAN THEY BE AFFORDED? 72. CHAPTER 7: CONCLUSIONS AND RECOMMENDATIONS 76. 7.1 THE CASE STUDY 76. 7.2 GENERAL CONCLUSIONS AND RECOMMENDATIONS 80. 7.3 RECOMMENDATIONS FOR FURTHER RESEARCH 82. BIBLIOGRAPHY 84. APPENDIX 1: PROCEDURE FOR PREDICTION OF HIGHWAY NOISE USING THE ONTARIO HIGHWAY NOISE METHOD 85. APPENDIX 2: DETAILED NOISE CALCULATIONS OF THE CONTROL AND FIVE ARCHETYPES 92. APPENDIX 3: DETAILED COST BREAKDOWN OF THE CONTROL AND FIVE ARCHETYPES 95. LIST OF TABLES 1. APPARENT HEIGHT OF SOURCE 2. CHART FOR COMBINING NOISE LEVELS 3. NOISE LEVELS AND LAND USE CLASSIFICATIONS 4. COMPARISON OF GREATER VANCOUVER (1971) AND DONLEY .(1968) NOISE LEVEL MEASUREMENTS 5. NOISE LEVEL CRITERIA FOR SPEECH 6. TYPICAL NOISE LEVELS OF COMMON SOUNDS 7. COMPARISON OF THE ARCHETYPES AND CHARACTERISTICS 8. GROSS NOISE LEVELS OF THE CONTROL DESIGN WITH 1, 2 AND 3 ELEMENT CALCULATIONS 9. CALCULATED NOISE LEVELS IN dBA L FOR THE CONTROL AND FIVE ARCHETYPES 10. COMPARISON OF ARCHETYPES WITH 65 + 2.5 TARGET STANDARD 11. COMPARISON OF ARCHETYPES WITH 58 + 2.5 TARGET STANDARD 12. COMPARISON OF NUMBERS OF VEHICLES V I S I B L E FROM STREET LEVEL WITH RESPECT TO FIVE ARCHETYPES AND CONTROL 13. AESTHETIC PREFERABILITY OF FIVE ARCHETYPES 14. CONSTRUCTION, LAND AND TOTAL COSTS FOR CONTROL AND FIVE ARCHETYPES 15. COMPARISON OF ARCHETYPES WITH 5 8 + 2 . 5 TARGET STANDARD 16. COMPARISON OF ARCHETYPES WITH 65 + 2 . 5 TARGET STANDARD 17. AESTHETIC PREFERABILITY OF THE FIVE ARCHETYPES 18. CONSTRUCTION, LAND AND TOTAL COSTS FOR CONTROL AND FIVE ARCHETYPES v i . PAGE 1. 18. 19. 20. 22. 25. 31. 47. 52. 55. 55. 59. 62. 72. 77. 77. 78. 78. v i i LIST OF FIGURES PAGE 1. THE EFFECT OF A CHANGE IN APPARENT HEIGHT OF SOURCE 4 2. CONTROL 1 7 3. ARCHETYPE 2 7 4. ARCHETYPE 3 7 5. ARCHETYPE 4 8 6. ARCHETYPE 5 8 7. ARCHETYPE 6 8 8. COQUITLAM TOWN CENTRE CASE STUDY 9 9. CONTROL 1 29 10. ARCHETYPE 2 29 11. ARCHETYPE 3 29 12. ARCHETYPE 4 30 13. ARCHETYPE 5 30 14. ARCHETYPE 6 30 15. GREATER VANCOUVER REGIONAL DISTRICT AND CASE STUDY LOCATION 36 16. CASE STUDY 37 17. ELEMENTS IN CONTROL 1 48 18. ELEMENTS IN ARCHETYPE 2 48 19. ELEMENTS IN ARCHETYPE 3 48 20. ELEMENTS IN ARCHETYPE 4 49 21. ELEMENTS IN ARCHETYPE 5 49 22. ELEMENTS IN ARCHETYPE 6 49 23. ARCHETYPE 4: 18 FOOT APPARENT HEIGHT 61 24. ARCHETYPE 6: 15 FOOT APPARENT HEIGHT 61 25. INTERSECTION DESIGNS FOR ARCHETYPES 2, 4, AND 6 64 CHAPTER 1: INTRODUCTION AND METHODOLOGY  1.1 INTRODUCTION R e c e n t l y , much a t t e n t i o n has been d i r e c t e d towards the o f f e n s i v e a s p e c t s o f urban a r t e r i a l t r a f f i c . Of p r i m a r y c o n c e r n t o th o s e l i v i n g c l o s e t o a r t e r i a l s i s t h e i n c r e a s e d n o i s e and a i r p o l l u t i o n , t h e d e t e r i o r a t i n g v i s u a l e n v i r o n m e n t and the danger t o p e d e s t r i a n s . H i g h volumes o f t r u c k t r a f f i c i n c r e a s e a l l t h e s e i l l e f f e c t s . A r e c e n t s u r v e y c o n d u c t e d i n Washington S t a t e (1) found t h a t the average d i f f e r e n c e between sound e m i s s i o n l e v e l s o f v e h i c l e s o f l e s s t h a n 6000 l b . G.V.W. and th o s e o f more t h a n 6000 l b . G.V.W. was 7 dBA. (See Ch a p t e r 2, S e c t i o n 2, f o r an e x a m i n a t i o n o f t h e measurement of t r a f f i c n o i s e . ) An i n c r e a s e o f 7 dBA i s s u b s t a n t i a l i n t h a t an i n c r e a s e o f 10 dBA i s p e r c e i v e d by the human e a r as b e i n g a d o u b l i n g i n l o u d n e s s . (2) C o n s i d e r i n g t h e p r e s e n t c o n d i t i o n s s u r r o u n d i n g u r b a n a r t e r i a l s c a r r y i n g h i g h p e r c e n t a g e s o f t r u c k t r a f f i c , what o p t i o n s do d e c i s i o n m a k e r s have w i t h r e s p e c t t o l e s s e n i n g o r a l l e v i a t i n g the i l l e f f e c t ? 1. I n t r o d u c e r e g u l a t i o n s s u c h as n o i s e c o n t r o l b y l a w s a p p l i c a b l e t o l o w e r i n g e m i s s i o n s from i n d i v i d u a l v e h i c l e s , o r r e g u l a t i o n s r e s t r i c t i n g h o u r s o f o p e r a t i o n . 2. D e s i g n a t e s p e c i a l r o u t e s such as t r u c k r o u t e s t o s e p a r a t e t h e most n o x i o u s v e h i c l e s f r o m t h e most s e n s i t i v e a r e a s ( i . e . r e s i d e n t i a l , s c h o o l and h o s p i t a l z o n e s ) . 3. A l t e r l a n d use p a t t e r n s t o s e p a r a t e s e n s i t i v e l a n d uses f r o m e s t a b l i s h e d a r t e r i a l s ( r e c i p r o c a l o f se c o n d o p t i o n ) . 4. L i m i t t h e volumes o f t h e most n o x i o u s v e h i c l e s by r e s t r i c t i n g , f o r i n s t a n c e , i n d u s t r i a l o u t p u t i n c r i t i c a l a r e a s . 5. I n t r o d u c e p h y s i c a l d e s i g n s w h i c h l e s s e n t h e d e l e t e r i o u s e f f e c t s o f v e h i c l e s by i n t e r c e p t i n g t r a f f i c n o i s e b e f o r e i t r e a c h e s p o t e n t i a l r e c e i v e r s . Much p u b l i c i n t e r e s t has been shown f o r t h e e s t a b l i s h m e n t and 2. e n f o r c e m e n t o f n o i s e c o n t r o l r e g u l a t i o n s . R e c e n t l y the G r e a t e r Vancouver R e g i o n a l D i s t r i c t p r o d u c e d a model n o i s e c o n t r o l b y l a w w h i c h c o u l d be e a s i l y a d o p t e d by any m u n i c i p a l i t y . However, o n l y one m u n i c i p a l i t y , Burnaby, has a d o p t e d suc h a bylaw. I f t r a f f i c n o i s e i s p e r c e i v e d as a s i g n i f i c a n t p r o b l e m then the r e a s o n more m u n i c i p a l i t i e s have n o t t u r n e d t o t h e b y l a w must be a t t r i b u t e d t o a p e r c e i v e d l a c k o f e n f o r c e a b i l i t y . The b u l k o f the model b y l a w i s d i r e c t e d t o l o w e r i n g the n o i s e l e v e l s e m i t t e d by i n d i v i d u a l v e h i c l e s . However, as more t h a n j u s t a few v e h i c l e s w o u l d r e q u i r e a l t e r a t i o n t o a c h i e v e r e q u i r e d r e d u c t i o n s i n n o i s e e m i s s i o n s , t h e m u n i c i p a l i t y i s a t t a c k i n g a p r o b l e m w h i c h s h o u l d more r e a l i s t i c a l l y be a t t a c k e d f r o m a f e d e r a l o r p r o v i n c i a l l e v e l and d i r e c t e d towards t h e manu-t f a c t u r e r s . I n a n u t s h e l l , i t appears t h a t s i g n i f i c a n t r e d u c t i o n s i n n o i s e l e v e l s cannot be a c h i e v e d t h r o u g h m u n i c i p a l a p p l i c a t i o n o f n o i s e c o n t r o l b y l a w s . The s econd and t h i r d a l t e r n a t i v e s i n v o l v e t h e c o o r d i n a t i o n o f l a n d use and d e s i g n a t i o n o f a r t e r i a l s . I n many cases t h i s has been a s u c c e s s f u l means o f d e a l i n g w i t h heavy t r a f f i c . A r t e r i a l s , e s p e c i a l l y t h o s e w i t h t r u c k t r a f f i c , a r e d e s i g n a t e d t h r o u g h zones s u c h a s w a r e h o u s i n g and m a n u f a c t u r i n g where t h e y c r e a t e t h e l e a s t i n c o m p a t i b i l i t y . However, f o r a number o f r e a s o n s t h i s c o n v e n i e n t l a n d use arrangement i s n o t always p o s s i b l e . Some-time s e s s e n t i a l i n d u s t r i a l zones a r e s u r r o u n d e d by r e s i d e n t i a l a r e a s and any t r u c k t r a f f i c must pass t h r o u g h t h e s e r e s i d e n t i a l zones t o r e a c h t h e i r d e s t i n a t i o n s . The s e c o n d and t h i r d o p t i o n s , o f a r r a n g i n g c o m p a t i b l e l a n d uses n e x t t o a r t e r i a l s o r d e s i g n a t i n g " t r u c k r o u t e s " , . c a n be s u c c e s s f u l i n l e s s e n -i n g d e l e t e r i o u s e f f e c t s b u t t h e s e o p t i o n s a r e n o t always a v a i l a b l e e s p e c i a l l y i n h i g h l y u r g a n i z e d e s t a b l i s h e d a r e a s . The f o u r t h o p t i o n o f l i m i t i n g i n d u s t r i a l a c t i v i t y has o n l y p a r t i a l a p p l i c a t i o n . C o n s i d e r a b l e revenue t h r o u g h t a x a t i o n i s g e n e r a t e d by i n d u s t r i a l and c o m m e r c i a l p r o p e r t y owners. O f t e n m u n i c i p a l i t i e s must r e l y on p r o p e r t y t a x revenues from t h e i n d u s t r i a l and c o m m e r c i a l s e c t o r s t o compensate f o r the expense o f s e r v i c i n g and p r o v i d i n g u t i l i t i e s i n r e s i d e n t i a l s e c t o r s . The l a s t o p t i o n , t h a t o f d e s i g n a l t e r n a t i v e s , i s l i k e t h e o t h e r s n o t o f u n i v e r s a l a p p l i c a b i l i t y n o r w i t h o u t l i m i t a t i o n s . R e c e n t l y i n Vancouver, however, e s p e c i a l l y as o p t i o n s i n v o l v i n g a l t e r i n g r o u t e s o r l a n d use have become l e s s f e a s i b l e , some d e s i g n a l t e r n a t i v e s have emerged. These n o i s e b a r r i e r s have p r e d o m i n a n t l y been i n t h e fo r m o f f e n c e s and berms ( e a r t h mounds). The p u r p o s e o f t h i s s t u d y i s t o examine d i f f e r e n t t y p e s o f d e s i g n a l t e r n a t i v e s . The f o l l o w i n g q u e s t i o n s are a d d r e s s e d : 1. What t y p e s o f t r a f f i c n o i s e b a r r i e r s can be u s e d on a r t e r i a l s ? 2. How e f f e c t i v e a r e t h e s e b a r r i e r s , e s p e c i a l l y when t h e r e may be h i g h p e r c e n t a g e s o f t r u c k t r a f f i c i n the v e h i c l e f l o w ? 3. B e s i d e s n o i s e a t t e n u a t i o n e f f e c t i v e n e s s , how do t h e s e b a r r i e r s s t a c k up i n terms o f a e s t h e t i c s , c i r c u l a t i o n ( a u t o and p e d e s t r i a n ) , and c o s t ? Why have t r u c k s been i s o l a t e d as a s i g n i f i c a n t f e a t u r e o f t h i s s t u d y ? E s s e n t i a l l y because o f t h e i r h i g h e r n o i s e e m i s s i o n s as p r e v i o u s l y d i s c u s s e d and t h e i r h i g h e r a p p a r e n t n o i s e s o u r c e . A p p a r e n t n o i s e s o u r c e h e i g h t r e f e r s t o an ave r a g e measurement o f where n o i s e i s . e m i t t e d i n r e l a t i o n t o t h e v e h i c l e f l o w . I f t h e v e h i c l e f l o w c o n s i s t s m a i n l y o f a u t o m o b i l e s , the n o i s e g e n e r a t e d can be assumed t o o r i g i n a t e a t a p p r o x i m a t e l y one f o o t above th e r o a d s u r f a c e . However, a dominant s o u r c e o f n o i s e on a d i e s e l t r u c k i s t h e e x h a u s t s t a c k , w h i c h i s a p p r o x i m a t e l y 10 t o 12 f e e t above t h e r o a d s u r f a c e . The f o l l o w i n g a r e d a t a c a l c u l a t e d i n a s t u d y e n t i t l e d " T r a f f i c N o i s e C o m p u t a t i o n " . (3) TABLE 1 APPARENT HEIGHT OF SOURCE (FOR USE IN BARRIER CONFIGURATION) P e r c e n t a g e T r u c k s Apparent. H e i g h t , o f ( p e r c e n t o f t o t a l f l o w ) Source ( f e e t ) 1 o r l e s s 1 2 2 5 3 10 5 20 7 30 o r g r e a t e r 9 The i n c r e a s e i n a p p a r e n t h e i g h t o f s o u r c e i s s u b s t a n t i a l and r e a c h e s a peak o f n i n e f e e t a t 30 p e r c e n t o f t h e t o t a l f l o w . T h i s f a c t o r has o b v i o u s i m p l i c a t i o n s i n r e s p e c t to' t h e e f f e c t i v e n e s s o f a l l t y p e s o f b a r r i e r s . An e s s e n t i a l a s p e c t o f n o i s e a t t e n u a t i o n i s t h a t t h e " l i n e o f s i g h t " from the s o u r c e t o t h e r e c e i v e r must be i n t e r c e p t e d by the b a r r i e r i f any s i g n i f i c a n t r e d u c t i o n i s e x p e c t e d . I f t h e a p p a r e n t h e i g h t o f t h e s o u r c e i s n i n e f e e t , assuming a p e r c e n t a g e o f t r u c k s i n t h e f l o w o f 30 p e r c e n t o r g r e a t e r , then t h e h e i g h t o f t h e b a r r i e r must l i k e w i s e be i n c r e a s e d t o be e f f e c t i v e . FIGURE 1: THE EFFECT OF A CHANGE IN APPARENT HEIGHT OF SOURCE 5 t X -• 20'— SS F i g u r e 1 i l l u s t r a t e s t h a t a t e n f o o t b a r r i e r can p r o v i d e a s u b s t a n t i a l b r e a k i n the " l i n e o f s i g h t " i f t h e a p p a r e n t s o u r c e i s one f o o t from t h e r o a d s u r f a c e ( l e s s than 1 p e r c e n t t r u c k s ) ; however, i f t h e a p p a r e n t h e i g h t i s n i n e f e e t (30 p e r c e n t o r g r e a t e r t r u c k s ) t h e r e i s no b r e a k i n the l i n e o f s i g h t w i t h t he r e s u l t t h a t any n o i s e w h i c h i s i n t e r c e p t e d i s n e g l i g i b l e i n r e s p e c t t o t h e dominant n i n e f o o t a p p a r e n t s o u r c e phenomenon. K e e p i n g i n mind t h e i n c r e a s e d n o i s e l e v e l s and h i g h e r a p p a r e n t s o u r c e w i t h h i g h volumes o f t r u c k t r a f f i c , t h i s s t u d y w i l l a t tempt t o e v a l u a t e t he e f f e c t i v e n e s s o f v a r i o u s d e s i g n a l t e r n a t i v e s when a p p l i e d t o a " h i g h p e r c e n t a g e o f t r u c k t r a f f i c i n t o t a l f l o w " s i t u a t i o n . 1.2 METHODOLOGY V a r i o u s d e s i g n a l t e r n a t i v e s a r e e v a l u a t e d p r i m a r i l y t h r o u g h a case s t u d y s i t u a t i o n w h i c h i n c o r p o r a t e s t h e e s s e n t i a l c r i t e r i o n o f a h i g h p e r c e n t a g e o f t r u c k t r a f f i c . The f i r s t s t a g e i n the s t u d y i s t o de t e r m i n e what f a c t o r s can be a l t e r e d by d e s i g n a l t e r n a t i v e s . I n o t h e r words, what can one p o t e n -t i a l l y e x p e c t a berm o r l o w e r e d r o a d b e d , f o r i n s t a n c e , t o a c c o m p l i s h . R e l e v a n t l i t e r a t u r e s u g g e s t s t h e f o l l o w i n g f a c t o r s are i m p o r t a n t v a r i a b l e s : 1. N o i s e . 2. A e s t h e t i c s . 3. C i r c u l a t i o n and s a f e t y ( v e h i c l e s and p e d e s t r i a n s ) . 4. C o s t . N o i s e and c o s t a r e d e a l t w i t h i n a q u a n t i t a t i v e c o n t e x t , w h i l e c i r c u l a t i o n - s a f e t y and a e s t h e t i c s a r e g i v e n q u a l i t a t i v e c o n s i d e r a t i o n . The i n v e s t i g a t i o n o f n o i s e a t t e n u a t i o n e f f e c t i v e n e s s i s d e a l t w i t h more e x t e n s i v e l y t h a n the o t h e r f a c t o r s . However, w e i g h t i n g o f the f a c t o r s i s n o t done as t h e r e i s no e m p i r i c a l e v i d e n c e t h a t any one o f them i s more i m p o r t a n t t h a n a n o t h e r . T h i s does n o t o v e r r u l e t h e s i t u a t i o n where d e c i s i o n m a k e r s m i g h t , 6. q u i t e l e g i t i m a t e l y , weigh c e r t a i n f a c t o r s o v e r o t h e r s . I n o t h e r words, i n a p a r t i c u l a r case t h e a p p r o p r i a t e d e s i g n i n terms o f n o i s e c o n t r o l , a e s t h e t i c v a l u e , and c i r c u l a t i o n m i g h t be c o m p l e t e l y o u t o f t h e q u e s t i o n i n terms o f c o s t . The c o n s i d e r a t i o n o f n o i s e i n v o l v e s t h e f o l l o w i n g : 1. N o i s e measurement and t h e s e l e c t i o n o f a n o i s e p r e d i c t i o n model. 2. S t a n d a r d s o f n o i s e l e v e l s w h i c h i d e a l l y s h o u l d be met by d e s i g n a l t e r n a t i v e s . F i v e d i f f e r e n t d e s i g n s are c o n s i d e r e d . The s e l e c t i o n o f t h e s e d e s i g n s i s b a s e d on p r i o r a s s u m p t i o n s about n o i s e a t t e n u a t i o n , a e s t h e t i c s , c i r c u l a -t i o n , s a f e t y and c o s t . Each d e s i g n i s d e s c r i b e d a c c o r d i n g t o t h e h y p o t h e -s i z e d advantages and d i s a d v a n t a g e s . F i g u r e s 2 th r o u g h 7 show i n c r o s s -s e c t i o n t h e d e s i g n a l t e r n a t i v e s . The case s t u d y i n v o l v e s g r a v e l t r u c k t r a f f i c e x p e c t e d t o t r a v e l t h r o u g h C o q u i t l a m ' s new Town C e n t r e Development (see F i g u r e 8 ) . I m p o r t a n t i n the case s t u d y i s a r e a s o n a b l e f o r e c a s t o f f u t u r e t r u c k and c a r volumes, i n o r d e r t o d e t e r m i n e what k i n d o f p r o t e c t i o n m i g h t be needed. F o r e c a s t s o f c a r and t r u c k volumes d e v e l o p e d by t r a f f i c e n g i n e e r i n g c o n s u l t a n t s f o r t h e D i s t r i c t o f C o q u i t l a m a r e employed. These f o r e c a s t s i n v o l v e c o n s i d e r a t i o n o f and as s u m p t i o n s about f u t u r e g r a v e l e x t r a c t i o n a c t i v i t y w h i c h g e n e r a t e s t h e t r u c k t r a f f i c . A f u r t h e r p r e d i c t i o n must be made c o n c e r n i n g t h e volumes o f t r a f f i c w h i c h w i l l be g e n e r a t e d by t h e town c e n t r e development and a n c i l l a r y r e s i d e n -t i a l growth. A d e s c r i p t i o n o f l a n d use a l o n g t he case s t u d y r o u t e f o l l o w s . Land use c o n s i d e r a t i o n i s i m p o r t a n t as d i f f e r e n t s t a n d a r d s , f o r i n s t a n c e , i n n o i s e l e v e l s a p p l y t o d i f f e r e n t l a n d uses. The n e x t s t a g e i n c o r p o r a t e s t he use o f t h e n o i s e p r e d i c t i o n model w h i c h was s e l e c t e d e a r l i e r . F i r s t , n o i s e l e v e l s a r e d e t e r m i n e d a c c o r d i n g t o t h e as s u m p t i o n s made c o n c e r n i n g f o r e c a s t s o f f u t u r e t r u c k and c a r volumes. These THE DESIGN ALTERNATIVES FIGURE 2: CONTROL, NO BARRIER CONFIGURATION -78 , , , , 1 ^ QgADS 3' /2' '2' /Z' /Z' fZ' /2f 3' FIGURE 3: VERTICAL RETAINED WALL 72 i 1 / Z ' / £ ' — ' 1 r 3' /Z' iZ' 3' FIGURE 4: EARTH SLOPE fZ' /Z' <t - i 1 r—r it' 3' /Z' W 3' '8 A 2 ' • tZ ' J J « o -DESIGN ALTERNATIVES (continued) FIGURE 5: BERM FIGURE 6: COMBINATION EARTH SLOPE-BERM w ' J <t I 1 A | r t f i • 1 1 >Z' /z' 3C 1 1 1 I I •5' / Z ' ,Z' 5 ' 1 FIGURE 7: COMBINATION EARTH SLOPE-BERM (WITH FULL PROTECTION) 10. n o i s e l e v e l s must be c a l c u l a t e d a t c r i t i c a l d i s t a n c e s f r o m t h e s o u r c e . F o r i n s t a n c e , i f t h e e n v i r o n m e n t f l a n k i n g the a r t e r i a l i s p e d e s t r i a n o r i e n t e d , n o i s e l e v e l s a t s t r e e t l e v e l l o c a t i o n s a r e c r u c i a l . L e v e l s a r e c a l c u l a t e d a t s p e c i f i c d i s t a n c e s f r o m t h e roadway as w e l l as at v a r i o u s e l e v a t i o n s t o p r e d i c t n o i s e g e n e r a t i o n i f l a n d use d e l i n e a t i o n s ( s u c h as town-house d e v e l -opment) s u g g e s t n o i s e l e v e l s a t v a r i o u s e l e v a t i o n s a r e c r u c i a l . The p r e d i c t e d n o i s e l e v e l s a t v a r i o u s l a t e r a l and v e r t i c a l d i s t a n c e s can now be compared t o e x i s t i n g s t a n d a r d s f o r s p e c i f i c l a n d use s i t u a t i o n s . F o l l o w i n g i s c o n s i d e r a t i o n o f t h e n o i s e a t t e n u a t i o n e f f e c t o f each o f t h e f i v e b a r r i e r c o n f i g u r a t i o n s a t t h e c r u c i a l l a t e r a l and v e r t i c a l d i s t a n c e s . The d e s i g n s can now be compared i n r e s p e c t t o t h e i r r e l a t i v e c a p a b i l i t i e s t o a t t e n u a t e n o i s e . A q u a l i t a t i v e e v a l u a t i o n o f each o f t h e d e s i g n s i s made i n r e s p e c t t o b o t h e f f i c i e n c y o f c i r c u l a t i o n , i n c l u d i n g s a f e t y , and a e s t h e t i c i m p a c t . The l a s t c r i t e r i o n i s c o s t . T h i s e v a l u a t i o n i s done i n c u r r e n t (1977) d o l l a r s and t h e c o s t s a r e s t a n d a r d i z e d t o f a c i l i t a t e c o m p a r i s o n by c o n s i d e r -i n g each d e s i g n i n r e s p e c t t o a one m i l e s t r e t c h o f roadway. The c o s t s a r e s e p a r a t e d w i t h i n each a l t e r n a t i v e so as t o r e v e a l what a s p e c t s o f each i n c u r s p e c i f i c a l l y what c o s t s . T h i s h e l p s t o i n d i c a t e what c o m b i n a t i o n s o r p o r t i o n s o f s o l u t i o n s m i g h t be a p p r o p r i a t e i n a g i v e n s i t u a t i o n i n r e s p e c t t o c o s t s . C o n c l u s i o n s a r e t h e n drawn w i t h r e s p e c t t o the s p e c i f i c case s t u d y s i t u a t i o n and t h e f i v e d e s i g n s c o n s i d e r e d . A t t h i s p o i n t i t i s p o s s i b l e t o compare each o f t h e d e s i g n s i n r e s p e c t t o t h e i r r e l a t i v e s a t i s f a c t i o n o f a l l t he c r i t e r i a . F o l l o w i n g the s p e c i f i c c o n c l u s i o n s g e n e r a l ones a r e made w i t h r e s p e c t t o any b r o a d e r a p p l i c a b i l i t y the r e s u l t s may s u g g e s t . A p r o c e d u r a l model i s i n t r o d u c e d s u g g e s t i n g the a p p r o p r i a t e s t e p s d e c i s i o n m a k e r s s h o u l d t a k e 11. i n e v a l u a t i n g the e f f e c t i v e n e s s and a p p l i c a b i l i t y o f d e s i g n a l t e r n a t i v e s . To summarize, t h e methodology i s as f o l l o w s : 1. S e l e c t i o n o f v a r i a b l e s c r u c i a l i n e v a l u a t i n g d e s i g n a l t e r n a t i v e s . 2. A n a l y s i s o f n o i s e measurement: a. S e l e c t i o n o f n o i s e p r e d i c t i o n model. b. S e l e c t i o n o f a p p r o p r i a t e s t a n d a r d s o f n o i s e l e v e l s r e l e v a n t f o r v a r i o u s l a n d uses. 3. S e l e c t i o n o f f i v e d e s i g n a r c h e t y p e s . 4. D e s c r i p t i o n o f t h e case s t u d y : a. P r e d i c t e d volumes o f t r u c k s and c a r s . b. Land use t y p e s b o r d e r i n g t h e case s t u d y r o u t e . 5. A p p l i c a t i o n o f t h e n o i s e p r e d i c t i o n model: a. N o i s e l e v e l s a t c r i t i c a l l a t e r a l and v e r t i c a l d i s t a n c e s f r o m roadway. b. Comparison o f l e v e l s f o u n d i n 5.a. w i t h s t a n d a r d s and ambient l e v e l s . c. A t t e n u a t i o n e f f e c t o f b a r r i e r s . d. C o n c l u s i o n s r e g a r d i n g n o i s e a t t e n u a t i o n e f f e c t i v e n e s s o f each d e s i g n . 6. Q u a l i t a t i v e e v a l u a t i o n o f a e s t h e t i c i m p a c t o f each d e s i g n . 7. Q u a l i t a t i v e e v a l u a t i o n o f c i r c u l a t i o n e f f e c t i v e n e s s o f each d e s i g n . 8. E v a l u a t i o n o f c o m p a r a t i v e c o s t s . 9. C o n c l u s i o n s i n c l u d i n g : a. C o n c l u s i o n s s p e c i f i c t o t h e case s t u d y . b. G e n e r a l c o n c l u s i o n s and a p p l i c a b i l i t y t o o t h e r s i t u a t i o n s i n v o l v i n g d e s i g n s o l u t i o n s , i n c l u d i n g the i n t r o d u c t i o n o f a p r o c e d u r a l model f o r d e c i s i o n m a k i n g i n r e s p e c t t o d e s i g n a l t e r n a t i v e s . 12. FOOTNOTES 1. R.N. F o s s , V e h i c l e N o i s e Study , F i n a l R e p o r t , P r e p a r e d f o r W a shington S t a t e Highway Commission, Department o f Highways, U n i v e r s i t y o f Was h i n g t o n , A p p l i e d P h y s i c s L a b o r a t o r y , S e a t t l e , W a s h i n g t o n , June 1972, pp. 18-45. R e f e r r e d t o i n J . J . H a j e k , " O n t a r i o Highway N o i s e P r e d i c t i o n Method" i n T r a n s p o r t a t i o n R e s e a r c h C i r c u l a r , Number 175, J a n u a r y 1976, p. .65. 2. K. L y n c h , S i t e P l a n n i n g , MIT P r e s s , 1962. 3. G.S. An d e r s o n , " T r a f f i c N o i s e C o m p u t a t i o n " , B o l t , Beranek and Newman I n c . , Cape Cod L e c t u r e S e r i e s , Cape Cod, C a l i f . , 1970, pp. 26-42. R e f e r r e d t o i n J . J . H a j e k , O n t a r i o Highway N o i s e P r e d i c t i o n Method, O n t a r i o , M i n i s t r y o f T r a n s p o r t a t i o n and Communications, 1975, p. 24. 13. CHAPTER 2: ANALYSIS OF NOISE MEASUREMENT  2.1 THE MEASUREMENT OF NOISE I t i s commonly assumed t h a t t h e d i f f e r e n c e between sound and n o i s e i s t h a t n o i s e i s m e r e l y unwanted sound. T h i s i s a s i m p l i s t i c s t a t e m e n t b u t i n t r o d u c e s t h e s i g n i f i c a n t a t t i t u d i n a l a s p e c t t o n o i s e p e r c e p t i o n . F o r the pu r p o s e s o f t h i s s t u d y , t r a f f i c sound w i l l be assumed t o be " n o i s e " . A t t i t u d -i n a l r e s p o n s e s t o t r a f f i c a r e b r i e f l y d i s c u s s e d i n the c o n c l u d i n g c h a p t e r o f t h i s s t u d y . The measurement o f n o i s e i s c o n v e n t i o n a l l y done by means o f the "A"-w e i g h t e d d e c i b e l s c a l e (dBA) d e f i n e d a s : ... a l o g a r i t h m i c s c a l e w h i c h i s one a t t h e t h r e s h o l d o f h e a r i n g and 140 a t the t h r e s h o l d o f p a i n . Each i n t e r v a l o f t e n d e c i b e l s i n d i c a t e s l e v e l o f sound energy t e n time s g r e a t e r t h a n b e f o r e ... A n o i s e twenty d e c i b e l s h i g h e r t h a n a n o t h e r has one h u n d r e d t i m e s the e n e r g y o f t h e l a t t e r , and so on. (1) A l t h o u g h sound p r e s s u r e l e v e l s i n c r e a s e by 10 time s w i t h e v e r y i n c r e a s e o f t e n d e c i b e l s , t h i s i n c r e a s e i s p e r c e i v e d by the human e a r as a p p r o x i m a t e l y t w i c e as l o u d . (2) The most s i g n i f i c a n t r e a s o n f o r u s i n g the " A " - w e i g h t e d s c a l e i s s u g g e s t e d by G a l l o w a y e t a l . : The p h y s i c a l measure o f n o i s e - sound l e v e l i n d e c i b e l s as measured on the s c a l e o f a s t a n d a r d sound l e v e l m e ter - was s e l e c t e d as b e i n g s t a t i s t i c a l l y i n d i s t i n g u i s h a b l e from the b e s t p s y c h o l o g i c a l l y d e r i v e d measures i n i t s r e l i a b i l i t y as a p r e d i c t o r o f human res p o n s e t o v e h i c l e n o i c e . (3) A method o f m e a s u r i n g n o i s e l e v e l s o v e r time i s n e c e s s a r y i n most s i t u -a t i o n s as l e v e l s a r e r a r e l y c o n s i s t e n t o v e r t i m e . Most r e s e a r c h work con-s u l t e d used e i t h e r L^^, L , _ Q , o r L ^ l e v e l s . These l e v e l s c o r r e s p o n d t o t h e p e r c e n t a g e o f ti m e o f w h i c h a c e r t a i n n o i s e l e v e l i s exceeded. F o r i n s t a n c e , 78 dBA on t h e L^^ l e v e l means t h a t f o r 90 p e r c e n t o f t h e time p e r i o d i n q u e s t i o n n o i s e l e v e l s e x c e e d 78 dBA. As the n a t u r e o f v e h i c u l a r t r a f f i c t e n d s t o be, e x c e p t i n t h e most h e a v i l y t r a f f i c k e d a r e a s , an e s s e n t i a l l y 14. peak l e v e l p r o b l e m , the L ^ Q l e v e l i s commonly r e f e r r e d t o i n n o i s e g e n e r a t i o n and b a r r i e r a t t e n u a t i o n s t u d i e s . I n o r d e r t o be c o n s i s t e n t w i t h t h i s L ^ Q s t a n d a r d t h i s s t u d y employs L ^ Q l e v e l measurement. 2.2 SELECTION OF THE NOISE PREDICTION MODEL The highway n o i s e p r e d i c t i o n method s h o u l d e n a b l e p l a n n e r s and d e s i g n e r s t o u t i l i z e f u l l y and e f f i c i e n t l y the l a n d s s u r r o u n d i n g highways and t o m i n i m i z e t h e a d v e r s e e f f e c t s o f highways on the en v i r o n m e n t . (4) N o i s e p r e d i c t i o n models have become i n c r e a s i n g l y more i m p o r t a n t i n h i g h -way d e s i g n i n r e c e n t y e a r s . D e s i g n e r s a r e r e l y i n g on models t o a g r e a t e r e x t e n t because t h e y a r e cheaper and f a s t e r t o use tha n making a c t u a l n o i s e measurements, and th e y s i m u l a t e c o n d i t i o n s w h i c h do n o t p r e s e n t l y e x i s t . F o r i n s t a n c e , i n t h e case a t hand, n e i t h e r t h e n o i s e g e n e r a t i n g n o r the b a r r i e r c o n d i t i o n s e x i s t a t p r e s e n t , b u t t h e e f f e c t s o f each must be c a l c u l a t e d . The most i m p o r t a n t c r i t e r i o n f o r a n o i s e model i s , o f c o u r s e , a c c u r a c y . Models d e v e l o p e d i n t h e U n i t e d S t a t e s , Canada, and B r i t a i n i n t h e l a s t t e n y e a r s have i n c r e a s i n g l y become more a c c u r a t e and comprehensive. Comprehensive i n t he se n s e t h a t t h e y a r e more r e l i a b l e i n d i v e r s e s i t u a t i o n s , s u c h as low volume c o n d i t i o n s , and i n c o r p o r a t e n e c e s s a r y a d j u s t m e n t s t o a c c o u n t f o r t r a f f i c c h a r a c t e r i s t i c s (volumes, s p e e d s , and p e r c e n t a g e s o f t r u c k t r a f f i c ) , t o p o g r a p h y ( v e g e t a t i o n , b a r r i e r s , and e l e v a t i o n s ) , and roadway c h a r a c t e r i s t i c s , ( g r a des and c o n f i g u r a t i o n s ) . (5) A f u r t h e r q u a l i f i c a t i o n n e c e s s a r y f o r s e l e c t i n g an a p p r o p r i a t e model i s t h a t i t be s i m p l e t o employ. Most p l a n n e r s and d e s i g n e r s do n o t have t h e t e c h n i c a l e x p e r t i s e n o r the time t o c o n s i d e r a complex model. W i t h t h e s e q u a l i f i c a t i o n s i n mind, t h r e e n o i s e p r e d i c t i o n models a re c o n s i d e r e d . One d e v e l o p e d i n B r i t a i n by Delaney ( 6 ) , a n o t h e r i n t h e U n i t e d S t a t e s by B o l t , Beranek and Newman I n c . ( 7 ) , and t h e t h i r d i n Canada by Ha j e k . ( 8 ) . The Delaney Method i s an e m p i r i c a l one d e r i v e d f r o m f i e l d d a t a c o l l e c t e d 15. i n E n g l a n d . L ^ Q sound l e v e l s ( t h e l e v e l w h i c h i s ex c e e d e d 10% o f t h e tim e ) were used t o d e r i v e t h e f o r m u l a : L 1 Q = 18.1 + 8.9 l o g V + 0.117 p + 16.2 l o g S where: V = t o t a l t r a f f i c volume i n v e h i c e l s p e r h o u r ; p = p e r c e n t a g e o f heavy v e h i c l e s ( w e i g h t g r e a t e r t h a n 1500 k g . ) ; and S = mean t r a f f i c s p e e d i n k i l o m e t e r s p e r h o u r . (9) The B o l t , Beranek and Newman (BBN) method i s b a s e d on a t h e o r e t i c a l t r a f f i c n o i s e s i m u l a t i o n model f r o m w h i c h a number o f e q u a t i o n s a r e d e r i v e d t o s u i t / d i f f e r i n g c o n d i t i o n s at t h e L , _ Q l e v e l ( n o i s e l e v e l w h i c h i s ex c e e d e d 50 p e r c e n t o f t h e t i m e ) . (10) A n o t h e r e q u a t i o n i s a p p l i e d t o a d j u s t t h e l e v e l s f r o m L ^ ^ t o L-|_o' H a j e k , i n d e v e l o p i n g the O n t a r i o N o i s e P r e d i c t i o n M o d e l , c o n d u c t s a c o m p a r a t i v e a n a l y s i s o f t h e BBN and Delaney models. (12) The p r e c i s i o n o f t h e two p r e d i c t i o n methods was e v a l u a t e d by u s i n g a s t a n d a r d d e v i a t i o n o f d i f f e r e n c e s between measured and c a l c u l a t e d sound l e v e l s ( i . e . s t a n d a r d e r r o r ) and by u s i n g an ave r a g e d i f f e r e n c e between measured and c a l c u l a t e d l e v e l s . The comparison was made f o r a l l 135 o b s e r v a t i o n s : 89 expressway o b s e r v a t i o n s , 46 nonexpressway o b s e r v a t i o n s ... (13) Haj e k f o u n d t h e BBN method f o r expressway l o c a t i o n s o v e r p r e d i c t e d on t h e average by .6 dBA ( n e g l i g i b l e ) and the s t a n d a r d d e v i a t i o n to be 2.7 dBA. However, i n nonexpressway c o n d i t i o n s , and t h i s i s o f d i r e c t r e l e v a n c e t o the case a t hand, the BBN method o v e r p r e d i c t e d L ^ Q n o i s e l e v e l s i n non-expressway c o n d i t i o n s by 6 dBA and o v e r e s t i m a t i o n s i n the o r d e r o f 10 dBA were common. (14) On t h e o t h e r hand, the Delaney method was e x t r e m e l y a c c u r a t e w i t h r e s p e c t t o low d e n s i t y ( v e h i c l e s p e r m i l e ) o b s e r v a t i o n s w i t h an average o v e r e s t i m a t i o n by the model o f o n l y 1.1 dBA. (15) The s t a n d a r d d e v i a t i o n o f t h e Delaney method, 2.69 dBA, was comparable t o the BBN method. ( 1 6 ) . 1 6 . I n an a t t e m p t t o improve on t h e two methods, H a j e k d e v e l o p s t h r e e e q u a t i o n s f o r L ^ Q » ^ ^ Q ' A N ^ ^ 5 - ^ ^ - l - 3 , ^ e l e v e l e q u a t i o n i s : L 1 Q = 5 2 . 7 + 1 1 . 2 l o g 1 Q ( V c + 3 V F C ) - 1 4 . 8 l ° g 1 0 D + 0 . 2 1 S whe r e : = t o t a l volume o f p a s s e n g e r c a r s (GVW <_ 1 0 , 0 0 0 l b . ) , i n v e h i c l e s / h o u r ; V = t o t a l volume o f t r u c k s (GVW > 1 0 , 0 0 0 l b . ) , i n v e h i c l e s / h o u r ; D = d i s t a n c e t o edge o f pavement o f the f i r s t t r a f f i c l a n e , i n f e e t ; and S = ave r a g e s p e e d o f t r a f f i c f l o w , i n m.p.h. (av e r a g e s p e e d o f a l l highway v e h i c l e s o v e r a g i v e n s e c t i o n o f a highway d u r i n g a s p e c i f i e d t i m e p e r i o d ) . ( 1 7 ) H a j e k ' s model improves the s t a n d a r d d e v i a t i o n o f 1 2 8 p r e d i c t e d v e r s u s o b s e r v e d c a l c u l a t i o n s t o 2 . 1 7 dBA. The s t a n d a r d e r r o r o f e s t i m a t e o f 2 . 1 7 s u g g e s t s t h a t i n 2 out o f 3 cases t h e p r e d i c t e d L ^ Q sound l e v e l s w i l l be w i t h i n ± 2 dBA ... o f t h e measured l e v e l s . ( 1 8 ) As H a j e k ' s model appears t o b e s t s u i t t h e c r i t e r i a o f a c c u r a c y , compre-h e n s i v e n e s s and s i m p l i c i t y , i t i s s e l e c t e d as the n o i s e p r e d i c t i o n method t o be u s e d i n t h e p r e s e n t s t u d y . The f o l l o w i n g i s a d e s c r i p t i o n o f some o f t h e maj o r c h a r a c t e r i s t i c s o f t h e method, e s p e c i a l l y t h o s e p e r t i n e n t t o t h e case s t u d y . A p p e n d i x 1 i s a p r o c e d u r a l o u t l i n e f o r use o f H a j e k ' s O n t a r i o N o i s e P r e d i c t i o n Model. I n r e s p e c t t o a c c u r a c y , i n a d d i t i o n t o i t s s m a l l e s t s t a n d a r d d e v i a t i o n , i t was c o n c l u d e d t h a t t h e O n t a r i o Method may o f t e n be more a c c u r a t e t h a n t h e s t a n d a r d method o f f i e l d measurement ( u s i n g 1 5 minute i n t e r v a l s ) b ecause i t was b a s e d on comprehensive t r a f f i c c o u n t s r a t h e r than 1 5 minute i n t e r v a l measurements w h i c h may n o t r e p r e s e n t c o n d i t i o n s o v e r b r o a d e r time p e r i o d s . ( 1 9 ) The e f f e c t o f d i s t a n c e i s d e a l t w i t h i n the O n t a r i o Method by a d e c r e a s e o f 4 . 5 dBA p e r d o u b l i n g o f d i s t a n c e f r o m t h e s o u r c e . ( 2 ) T h i s c o r r e s p o n d s t o the f i n d i n g s o f e a r l i e r n o i s e measurement s t u d i e s s u c h as t h e N a t i o n a l C o o p e r a t i v e Highway R e s e a r c h Program (NCHRP) Repo r t 1 4 4 ( 2 1 ) , w h i c h a l s o 17. employed t h e 4.5 dBA p e r d o u b l i n g o f d i s t a n c e c r i t e r i a . T r u c k t r a f f i c i s d e a l t w i t h by d i v i d i n g v e h i c l e s i n t o two c a t e g o r i e s : t h o s e l e s s than 10,000 l b . i n GVW and t h o s e more th a n 10,000 l b . (Most a u t o m o b i l e s w e i g h l e s s t h a n 4,000 l b . , w h i l e d i e s e l t r u c k s w e i g h 2 0 , 0 0 0 ' l b . and more.) I n o r d e r t o use b o t h l i g h t and heavy w e i g h t v e h i c l e s i n t h e same e q u a t i o n , t r u c k volumes a r e m u l t i p l i e d by a c o e f f i c i e n t o f 3 and added t o v e h i c l e volumes. The e f f e c t o f the m u l t i p l i c a t i o n c o e f f i c i e n t o f 3 i s s i m i l a r t o an i n c r e a s e i n n o i s e l e v e l s o f 5 dBA. (22) T h i s i s comparable t o t h e f i n d i n g s i n t h e W a shington S t a t e Study where a 7 dBA d i f f e r e n c e was f o u n d between v e h i c l e s w i t h GVW above and b e l o w 6,000 l b . (23) V e h i c l e s p e e d was f o u n d t o be h i g h l y c o r r e l a t e d w i t h n o i s e l e v e l s . A t n o i s e l e v e l s were d e t e r m i n e d t o change a t a r a t e o f 0.21 times t h e change i n speed. T h i s s p e e d - n o i s e c o r r e l a t i o n a l s o a p p l i e d t o t r u c k s . (24) N o t a l l t h e a d j u s t m e n t v a r i a b l e s p r e s e n t e d i n t h e O n t a r i o N o i s e P r e d i c t i o n Model ( A p p e n d i x 1) are used i n the p r e s e n t case s t u d y , as n o t a l l o f them a r e a p p l i c a b l e t o t h e case s t u d y s i t u a t i o n . However, t h e means by w h i c h the O n t a r i o Method i s s p e c i f i c a l l y employed i s d e s c r i b e d i n C h a p t e r 4, S e c t i o n 2, " A p p l i c a t i o n o f t h e N o i s e P r e d i c t i o n M o d el". 2.3 SELECTION OF APPROPRIATE STANDARDS FOR NOISE LEVELS Two b a s i c approaches a r e u t i l i z e d i n e s t a b l i s h i n g s t a n d a r d s f o r n o i s e l e v e l s . The f i r s t i n v o l v e s r e l a t i n g the v e h i c l e n o i s e l e v e l s t o the ambient n o i s e l e v e l (ambient d e f i n e d as t h a t n o i s e l e v e l w h i c h e x i s t s p r i o r t o the c o n s i d e r a t i o n o f an a d d i t i o n a l n o i s e s o u r c e ) . The s e c o n d i n v o l v e s c o n s i d e r -i n g the n o i s e s o u r c e i n r e s p e c t t o t a s k i n t e r f e r e n c e s u c h as s p e e ch o r s l e e p i n t e r f e r e n c e . T h i s s t u d y a t t e m p t s t o combine the ambient l e v e l and t a s k i n t e r f e r e n c e a p p r o a c h e s . Task i n t e r f e r e n c e i s i s o l a t e d t o speech i n t e r f e r e n c e as i t i s assumed n o i s e g e n e r a t i o n i n . t h e . case s t u d y s i t u a t i o n ( d e s c r i b e d i n C h a p t e r 3, S e c t i o n 2) w i l l be s u b s t a n t i a l l y l o w e r a t n i g h t , 18. when t h e r e w o u l d be n e g l i g i b l e t r u c k t r a f f i c and c o n s i d e r a b l y l o w e r volumes o f a l l t y p e s o f v e h i c l e s . I n c o n s i d e r a t i o n o f a mbient l e v e l s , two e s s e n t i a l f a c t o r s must be k e p t i n mind. The f i r s t i s , i s the ambient l e v e l a d e s i r a b l e g o a l t o a c h i e v e o r d u p l i c a t e ? T hat i s , by m a t c h i n g ambient l e v e l s one m i g h t be o v e r l y p r o t e c t i v e - n o t as much p r o t e c t i o n i s n e c e s s a r y . On the o t h e r h and, and more o f t e n t h i s i s t h e c a s e , t h e ambient l e v e l may a l r e a d y be t o o h i g h and t h e r e f o r e s h o u l d be i g n o r e d i n terms o f a c h i e v i n g e q u a l l e v e l s . The s e c o n d f a c t o r t o keep i n mind i s t h a t by m e r e l y m a t c h i n g ambient n o i s e l e v e l s one a c t u a l l y e x p e r i e n c e s an i n c r e a s e i n o v e r a l l n o i s e g e n e r a t i o n . I f two s o u r c e s each p r o d u c e n o i s e l e v e l s o f 67 dBA t h e a d d i t i v e e f f e c t i s 70 dBA. T a b l e 2 i l l u s t r a t e s t h i s phenomenon. TABLE 2: CHART FOR COMBINING NOISE LEVELS 4 J CO ' ^ H CO CO > iH CD CO iH •H M O CO CO JS P 60 •H •H O •U -W (3 CU TJ 0 CO CO U o nj C H — \ \ \ V ' Z 3 4- 5 C ,7 8 ? /V / / ,z ,3 ,+ D i f f e r e n c e i n D e c i b e l s between two l e v e l s b e i n g added From: A. P e t e r s o n e t a l . , Handbook o f N o i s e Measurement, C o n c o r d , Mass. G e n e r a l R a d i o , 1972. T h i s o b v i o u s , b u t a l l t o o o f t e n i g n o r e d , f a c t o r d e m o n s t r a t e s t h a t p o l i c i e s b a s e d on a d h e r i n g t o ambient l e v e l s a l o n e can r e s u l t i n e v e r - i n c r e a s i n g n o i s e l e v e l s . F o r t h i s r e a s o n , as ambient l e v e l s a r e p a r t o f t h e c r i t e r i o n f o r s t a n d a r d s i n t h i s s t u d y , the n o i s e e m i t t e d from e x i s t i n g l o c a l t r a f f i c w i l l a l s o be i n c l u d e d i n measurement p r e d i c t i o n . The o n l y n o i s e e m i s s i o n s w h i c h w i l l n o t be i n c l u d e d are t h o s e f r o m s o u r c e s o t h e r t h a n v e h i c l e s . These e m i s s i o n s w i l l be assumed t o be n e g l i g i b l e as t h e r e i s no heavy c o m m e r c i a l o r i n d u s t r i a l l a n d use f l a n k i n g t he roadway. (Land use a l o n g the c a s e s t u d y r o u t e i s d i s c u s s e d i n d e t a i l i n C h a p t e r 3, S e c t i o n 2.) H a v i n g d e a l t w i t h the a d d i t i v e e f f e c t , t h e f i r s t p r o b l e m o f w h e t h e r ambient l e v e l s s h o u l d be a d h e r e d t o w i l l now be a d d r e s s e d . R e s u l t s f r o m A Community N o i s e Survey o f t h e G r e a t e r Vancouver R e g i o n a l D i s t r i c t , a s t u d y c o n d u c t e d by B a r r o n and S t r a c h a n , a r e p r e s e n t e d i n t a b l e 3. (25) TABLE 3 NOISE LEVELS AND LAND USE CLASSIFICATIONS LAND ZONE DAY 7 am-10 pm NIGHT 10 pm-7 am L 9 0 L 5 0 L 1 0 L 9 0 L 5 0 L 1 0 INDUSTRIAL 49 58 69 44 52 64 COMMERCIAL 51 62 72 . 43 52 66 RESIDENTIAL 42 51 64 35 44 55 RURAL 36 45 58 32 42 53 A l l l e v e l s shown i n dBA. From B a r r o n and S t r a c h a n , C o n s u l t i n g A c o u s t i c a l E n g i n e e r s , A Community N o i s e Survey o f the G r e a t e r Vancouver R e g i o n a l D i s t r i c t , p r e p a r e d f o r t he G. V.R.D., 1971. To d e t e r m i n e w h e t h e r t h e ambient l e v e l s p r e s e n t e d a r e e i t h e r t oo h i g h o r t o o low i n terms o f r e a s o n a b l e d u p l i c a t i o n i s a l e n g t h y t a s k , beyond t h e scope o f t h i s s t u d y . I t w o u l d i n v o l v e m aking measurements i n many a r e a s w i t h d i f f e r i n g l a n d uses and d e v e l o p i n g c r i t e r i a f o r d e c i d i n g w h i c h l e v e l s s h o u l d be a d h e r e d t o . However, i n as much as B a r r o n and 2 0 . S t r a c h a n ' s . f i g u r e s match t h o s e measured i n a n o t h e r s t u d y , t h e Vancouver a r e a ambients can be assumed t o be r e a s o n a b l y r e p r e s e n t a t i v e . A s t u d y by Donley r e v e a l s r e s i d e n t i a l ambients measured i n m i d - A t l a n t i c s t a t e s ( 1 9 6 7 ) w h i c h a r e i d e n t i c a l t o t h o s e l a t e r measured ( 1 9 7 1 ) i n t h e Vancouver r e g i o n . The comparison i s i n T a b l e 4 . ( 2 6 ) TABLE 4 COMPARISON OF GREATER VANCOUVER ( 1 9 7 1 ) AND DONLEY ( 1 9 6 8 ) NOISE LEVEL MEASUREMENTS Survey L e v e l s (dBA) L 1 0 L 5 0 L 9 0 1 . G r e a t e r V a n c o u v e r 1 9 7 1 2 . Donley 1 9 6 8 6 4 5 1 4 2 6 4 5 1 4 2 R e g a r d i n g the ambient l e v e l s f o r the Vancouver r e g i o n p r e s e n t e d by B a r r o n and S t r a c h a n ( T a b l e 3 ) , t h e r e a r e two l e v e l s w h i c h a r e p a r t i c u l a r l y p e r t i n e n t . These a r e 6 4 dBA (L-^Q) f o r daytime r e s i d e n t i a l a r e a s and 7 2 dBA ( L ^ Q ) f o r daytime c o m m e r c i a l a r e a s . There are a number o f re a s o n s f o r b e l i e v i n g t h e 7 2 dBA ( L ^ Q ) measurement f o r c o m m e r c i a l a r e a s i s too h i g h i n r e s p e c t t o e s t a b l i s h i n g a s t a n d a r d f o r d u p l i c a t i o n . The f i r s t i s t h a t t h e com m e r c i a l l e v e l o f 7 2 dBA (L-^Q) i s h i g h e r t h a n t h e 6 9 dBA ( L ^ g ) l e v e l f o r i n d u s t r i a l a r e a s . T h i s s u g g e s t s the c o m m e r c i a l a r e a measurements i n c l u d e d heavy as w e l l as l i g h t c o m m e r c i a l t r a f f i c . As t h e co m m e r c i a l a r e a i n q u e s t i o n i s d e s c r i b e d as i n t e n s i v e c o m m e r c i a l n o i s e l e v e l s c o u l d be e x p e c t e d t o be l o w e r t h a n 7 2 dBA. How much l o w e r s h o u l d t h e standard.be? There a r e two arguments w h i c h s u g g e s t t h e s t a n d a r d s h o u l d be c l o s e r t o the 6 4 dBA l e v e l . F i r s t l y , t h e r e i s e x p e c t e d t o be some r e s i d e n t i a l use i n the comm e r c i a l a r e a i n t h e fo r m o f r e n t a l a p a r t m e n t s and h o t e l s . ( T h i s w i l l be 21. d e t a i l e d l a t e r i n t h e s e c t i o n on t h e case s t u d y r o u t e l a n d use.) T h i s i n d i c a t e s t h a t n o i s e l e v e l s s h o u l d be more c l o s e l y r e l a t e d t o r e s i d e n t i a l a mbients t h a n c o m m e r c i a l ones. S e c o n d l y , w i t h the emphasis on i n t e n s i v e c o m m e r c i a l l a n d use p e d e s t r i a n a c t i v i t y w i l l be p r e v a l e n t . T h i s f u r t h e r s u g g e s t s an o u t d o o r n o i s e l e v e l s i m i l a r t o r e s i d e n t i a l a r e a s w o u l d be p r e f e r a b l e . W i t h r e s p e c t t o the c o m m e r c i a l a r e a i n t h e case s t u d y , i t i s p r o p o s e d t h a t 6 4 dBA (L-^o^ s h o u l d be a d o p t e d as an ambient s t a n d a r d . I t i s emphasized t h a t 6 4 dBA (L^g) r e p r e s e n t s a rough guide o r s u g g e s t s a d e s i r a b l e l e v e l , n o t an a b s o l u t e l e v e l w h i c h somehow d i v i d e s a c c e p t a b l e from u n a c c e p t -a b l e . Three more l a n d uses w h i c h f l a n k t h e roadway - c i v i c , s c h o o l and p a r k and open spaces - a r e n o t t r e a t e d s p e c i f i c a l l y i n t h e B a r r o n and S t r a c h a n s t u d y n o r i n o t h e r ambient l e v e l measurement s t u d i e s c o n s u l t e d . I t i s t h o u g h t t h a t t h e s c h o o l and c i v i c l a n d uses s h o u l d assume an ambient s t a n d a r d no h i g h e r t h a n t h e 6 4 dBA ( l - ^ r e s i d e n t i a l and c o m m e r c i a l one due t o the e x t e n s i v e p e d e s t r i a n and o u t d o o r a c t i v i t y w h i c h w i l l o c c u r and t h e n e c e s s a r y a t t e n t i o n w h i c h must be p a i d towards a q u i e t e n v i r o n m e n t f o r s t u d y . The c i v i c a r e a c o u l d i n c l u d e a c e n t e r f o r p e r f o r m i n g a r t s w h i c h w o u l d a d d i t i o n -a l l y s u g g e s t a l e v e l s i m i l a r t o t h e r e s i d e n t i a l ambient. The p a r k a r e a p r e s e n t s a s p e c i a l p r o b l e m . I f i t was a s m a l l p a r k s i m i l a r t o t h o s e i n most o f t h e Vancouver a r e a , the ambient l e v e l s w o u l d l i k e l y be s i m i l a r t o the s u r r o u n d i n g , t y p i c a l l y r e s i d e n t i a l a r e a s . However, a l a r g e r p a r k c o u l d be c o n s i d e r a b l y q u i e t e r and p r e f e r a b l y have an ambient l e v e l s i m i l a r t o t h e r u r a l l a n d use c l a s s i f i c a t i o n i n B a r r o n and S t r a c h a n ' s s t u d y w h i c h i s 5 8 dBA ( L ^ Q ) . As the p a r k i n t h e case s t u d y i s t h i s l a r g e r v a r i e t y i t i s s u g g e s t e d t h a t t h e 5 8 dBA be a d o p t e d as an ambient s t a n d a r d . To summarize t h e ambient l e v e l d i s c u s s i o n , two l e v e l s have been s u g g e s t e d as a p p r o p r i a t e : 6 4 dBA ( L ) f o r r e s i d e n t i a l , c o m m e r c i a l , c i v i c and s c h o o l 2 2 . a r e a s and 5 8 dBA (L-^Q) f o r the p a r k a r e a . A g a i n i t i s emphasized t h a t t h e s e l e v e l s must be t r e a t e d as g e n e r a l g u i d e s , n o t a b s o l u t e i n d i c a t o r s . I n a d d i t i o n t o ambient l e v e l s , c o n s i d e r a t i o n o f t a s k i n t e r f e r e n c e i s th e second means o f e s t a b l i s h i n g s t a n d a r d s f o r n o i s e l e v e l s . The s p e c i f i c t a s k w h i c h was chosen i s t h a t o f s p e e c h . Speech i n t e r f e r e n c e i s p a r t i c u l a r l y r e l e v a n t t o t h e case s t u d y because i n a l l l a n d use s i t u a t i o n s the p o t e n t i a l f o r p e d e s t r i a n and o u t d o o r a c t i v i t y e x i s t s , t h e r e f o r e e f f e c t i v e o u t d o o r communication i s n e c e s s a r y . Below i s a t a b l e p r e s e n t e d i n Highway N o i s e ;  Measurement, S i m u l a t i o n , and M i x e d R e a c t i o n s . TABLE 5. NOISE LEVEL CRITERIA FOR SPEECH OUTDOOR TRAFFIC NOISE LEVEL (dBA) OUTDOOR SPEECH COMMUNICATION INDOOR SPEECH COMMUNICATION 7 5 R a i s e d v o i c e a t 1 - 2 f e e t N ormal v o i c e a t 3 - 1 0 f e e t 6 5 Normal v o i c e a t 2 - 5 f e e t N ormal v o i c e at 1 0 - 2 5 f e e t R a i s e d v o i c e a t 5 - 1 0 f e e t Q u i e t v o i c e a t 5 - 1 0 f e e t 5 5 Normal v o i c e a t 5 - 1 5 f e e t R a i s e d v o i c e a t 1 0 - 4 0 f e e t S a t i s f a c t o r y f o r c o n f e r e n c e a t 1 5 f o o t t a b l e From W.J. G a l l o w a y e t a l . , o f B o l t , Beranek and Newman, Highway  N o i s e : Measurement, S i m u l a t i o n and M i x e d R e a c t i o n s , NCHRP R e p o r t 7 8 , 1 9 6 9 , p. 1 8 . T h i s t a b l e i n d i c a t e s w h e t h e r one must speak i n a q u i e t , n o r m a l o r r a i s e d v o i c e t o be r e a s o n a b l y h e a r d i n r e s p e c t t o t r a f f i c n o i s e l e v e l s o f 7 5 dBA, 6 5 dBA, and 5 5 dBA. A g a i n r e f e r r i n g t o the predominance o f o u t d o o r 2 3 . a c t i v i t y i n t h e case s t u d y s i t u a t i o n , t he " o u t d o o r speech communication" l e v e l o f 6 5 dBA seems most a p p r o p r i a t e . A t t h i s l e v e l one can speak i n a n o r m a l v o i c e a t 2 t o 5 f e e t from t h e o t h e r p e r s o n and i n a r a i s e d v o i c e at 5 t o 1 0 f e e t . F u r t h e r s u p p o r t f o r a c c e p t i n g t h i s l e v e l i s b a s e d on t h e as s u m p t i o n t h a t 6 5 dBA w o u l d be c o n s i d e r e d i n the L ^ Q c o n t e x t . That i s , f o r o n l y 1 0 p e r c e n t o f t i m e i s one c o n f i n e d by speech i n t e r f e r e n c e h i g h e r t h a n 6 5 dBA. F o r 9 0 p e r c e n t o f t h e t i m e speech i n t e r f e r e n c e i s l e s s d i s r u p t i v e . Combining t h e r e s u l t s f r o m t h e c o n s i d e r a t i o n o f e x i s t i n g ambient n o i s e l e v e l s and speech i n t e r f e r e n c e 6 5 dBA (L-^Q) appears t o be a r e a s o n a b l e t a r g e t n o i s e l e v e l s t a n d a r d . 5 8 dBA (L-^g) w i l l be r e t a i n e d f o r t h e p a r k a r e a as s p e c i a l a t t e n t i o n f o r even l o w e r n o i s e l e v e l s i n t h i s a r e a i s w a r r a n t e d , as was p r e v i o u s l y d i s c u s s e d . The 6 5 ± 2 . 5 dBA t a r g e t s t a n d a r d i s s u p p o r t e d by M a r s h a l l ' s f i n d i n g s ( 2 7 ) i n t h a t a l t h o u g h he l o o k e d a t v a r i o u s e x i s t i n g s t a n d a r d s f o r n o i s e l e v e l s i n r e s p e c t t o r e s i d e n t i a l a r e a s r a n g i n g f r o m 5 6 dBA t o 7 0 dBA he c o n c l u d e d t h a t 6 5 dBA 0->^_Q) was t h e most a p p r o p r i a t e l e v e l c o n s i d e r i n g b o t h ambient l e v e l s and speech i n t e r f e r e n c e c r i t e r i a . ( 2 8 ) I d e a l l y one w o u l d e x p e c t a range o f l e v e l s r e l a t e d t o v a r i o u s t y p e s o f l a n d uses. However, r e s e a r c h i n t h i s a r e a has n o t been t h a t s u b s t a n t i a l . One s t u d y , t h e NCHRP 1 1 7 ( U . S . ) , w h i c h does d e l i n e a t e s t a n d a r d s f o r d i f f e r e n t l a n d uses p r e s e n t s l e v e l s w h i c h a r e i n t h e o r d e r o f 1 0 dBA l o w e r t h a n t h o s e c o n s i d e r e d h e r e . ( 2 9 ) The NCHRP 1 1 7 f i g u r e s a r e b a s e d on speech i n t e r f e r -ence so one w o u l d e x p e c t them t o c o r r e s p o n d t o t h e f i g u r e i n T a b l e 5 . However, t h e r e i s no i n d i c a t i o n g i v e n i n the NCHRP r e p o r t about t h e l e v e l o f speech w h i c h i s r e q u i r e d ( i . e . q u i e t , n o r m a l o r r a i s e d v o i c e ) n o r t h e d i s t a n c e between t h o s e communicating. T h e r e f o r e t h e NCHRP 1 1 7 f i g u r e s must be r e j e c t e d . 2 4 . To s u g g e s t t h a t 6 5 dBA ( L ^ Q ) and 5 8 dBA C L - ^ Q) s h o u l d be c o n s i d e r e d a b s o l u t e o r p r e c i s e d i v i d i n g l i n e s i s e r r o n e o u s on two a c c o u n t s . F i r s t l y , t h e means o f m e a s u r i n g n o i s e l e v e l s w i t h t h e O n t a r i o method i s o n l y a c c u r a t e t o a p p r o x i m a t e l y ± 2 . 5 dBA (as e a r l i e r d i s c u s s e d t h e s t a n d a r d d e v i a t i o n i s 2 . 1 7 dBA). T h e r e f o r e a t a r g e t s t a n d a r d o f 5 8 ± 2 . 5 dBA ( L 1 Q ) f o r t h e p a r k a r e a and 6 5 ± dBA (L - ^ Q) f o r t h e o t h e r l a n d use a r e a s can o n l y be e x p e c t e d . The second r e a s o n f o r s u g g e s t i n g a ± 2 . 5 dBA range i s t h a t i t i s v e r y d i f f i c u l t f o r t he human e a r t o d i s t i n g u i s h d i f f e r e n c e s i n n o i s e l e v e l s l e s s t h a n 5 dBA. ... t h e range o f v a r i a t i o n n o r m a l l y e n c o u n t e r e d i n the r e a c t i o n o f r e s i d e n t s o f a community t o a g i v e n n o i s e i s s u f f i c i e n t l y w ide t h a t a change o f n o i s e l e v e l o f l e s s than 5 dB w o u l d n o t p r o d u c e a s i g n i f i c a n t change i n the g e n e r a l p a t t e r n o f r e a c t i o n t o t h e n o i s e . ( 3 0 ) I n summary, two s t a n d a r d s w h i c h w i l l be used as g u i d e s have been s e l e c t e d u s i n g b o t h ambient l e v e l and speech i n t e r f e r e n c e c r i t e r i a : 6 5 ± 2 . 5 dBA C L - J ^ f o r r e s i d e n t i a l , c o m m e r c i a l , c i v i c and s c h o o l l a n d use a r e a s , and 5 8 ± 2 . 5 dBA C L - ^ Q) f o r t h e p a r k a r e a . T a b l e 6 i s p r e s e n t e d i n o r d e r t o i n d i c a t e t h e t y p e s o f a c t i v i t i e s t h a t w o u l d g e n e r a t e t h e s e n o i s e l e v e l s . 25. TABLE 6 TYPICAL NOISE LEVELS OF COMMON SOUNDS ROCKET ' AIRPLANE - r CITY STREET - — • — :  NOISY OFFICE • AUTOMOBILE ; ; CONVERSATION ^ — HOME : QUIET OFFICE • WHISPER -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130. A-SCALE SOUND PRESSURE LEVEL [.dB (A) ] from A r c h i t e c t u r a l I m p l i c a t i o n s o f Urban N o i s e , T . J . S c h u l t z , B.B. & W. I n c . , Cambridge, Mass., A.I.A. R e s e a r c h e r ' s C o n f e r e n c e , 1969. 26. FOOTNOTES 1. D. M a r s h a l l , A M i n i m a l Community Impact Urban Freeway, t h e s i s f o r t h e S c h o o l o f Community and R e g i o n a l P l a n n i n g , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1976, p. 46, q u o t e d from K. L y n c h , S i t e P l a n n i n g , M.I.T. P r e s s , 1962. 2. E f f e c t s o f T r a f f i c and Roads on t h e Enviro n m e n t i n Urban A r e a s , a r e p o r t p r e p a r e d by the O r g a n i z a t i o n f o r R e s e a r c h and Development, P a r i s , J u l y 1973, p. 13. 3. W.J. G a l l o w a y e t a l . o f B o l t , Beranek and Newman, Highway N o i s e ;  Measurement, S i m u l a t i o n and M i x e d R e a c t i o n s , NCHRP Repo r t 78, 1969, p. 1. 4. J . J . H a j e k , " O n t a r i o N o i s e P r e d i c t i o n Method" i n T r a n s p o r t a t i o n R e s e a r c h  C i r c u l a r , No. 175, 1976, p. 59. 5. H.M. R u p e r t , " N o i s e P r e d i c t i o n M o d e l s - T h e i r I m p o r t a n c e as a K e y s t o n e i n A p p l y i n g N o i s e S t a n d a r d s " i n TRC, No. 175, 1976, p. 15. 6. M.E. Delaney, "A P r a c t i c a l Scheme f o r P r e d i c t i o n N o i s e L e v e l s I, A r i s i n g f r o m Road T r a f f i c , NPL A c o u s t i c s R e p o r t , Ac 57, E n g l a n d , J u l y 1972, 1972, pp. 5-18. 7. C.G. Gordon e t a l . o r B o l t , Beranek and Newman, Highway N o i s e ; A D e s i g n  Guide f o r Highway E n g i n e e r s , NCHRP R e p o r t 117, 19 71. 8. J . J . H a j e k , ^p_. c i t . , pp. 59-69. 9. i b i d . , p. 61. 10. C.G. Gordon e t a l . , _op_. c i t . , p. 9. 11. i b i d . , p. 12. 12. J . J . H a j e k , ^p_. c i t . , p. 59. 13. i b i d . , P- 61. 14. i b i d . , P- 61. 15. i b i d . , P- 61. 16. i b i d . , P- 64. 17. i b i d . , P- 64. 18. i b i d . , P- 64. 19. i b i d . , P- 69. 20. i b i d . , P- 65. 21. B.A. K u g l e r e t a l . , o f B o l t , Beranek and Newman, Highway N o i s e : A F i e l d  E v a l u a t i o n o f T r a f f i c N o i s e R e d u c t i o n Measures, NCHRP Repo r t 144, 1973, p. 24. 27. 22. J . J . H a j e k , £p_. c i t . , p. 65. 23. i b i d . , p. 65. 24. i b i d . , p. 68. 25. B a r r o n and S t r a c h a n , C o n s u l t i n g A c o u s t i c a l E n g i n e e r s , A Community  N o i s e Survey o f t h e G r e a t e r V a n c o u v e r R e g i o n a l D i s t r i c t , p r e p a r e d f o r t h e G.V.R.D. , 1971. 26. i b i d . , p. 18. 27. D. M a r s h a l l , op_. c i t . , p. 48. 28. i b i d . , p. 51. 29. C. G. Gordon e t a l . , op_. c i t . , p. 30. 30. i b i d . , p. 23, q u o t e d from S t e v e n s e t a l . , "A Community's R e a c t i o n t o n o i s e : Can I t Be F o r e c a s t ? " , N o i s e C o n t r o l , 1, 63, 1955. CHAPTER 3: DESCRIPTIONS OF THE ARCHETYPES AND THE CASE STUDY 28. 3.1 DESCRIPTION OF THE CONTROL AND FIVE ARCHETYPES F i g u r e s 9 t h r o u g h 14 a r e I l l u s t r a t i o n s o f t h e C o n t r o l and the f i v e a r c h e t y p e s . T a b l e 7 i s a comparison o f the a r c h e t y p e s w i t h r e s p e c t t o the e s s e n t i a l c h a r a c t e r i s t i c s o f each. These c h a r a c t e r i s t i c s a r e : 1. T o t a l v e r t i c a l h e i g h t o f b a r r i e r . 2. H e i g h t o f f e n c e s . 3. F u l l p r o t e c t i o n / P a r t i a l p r o t e c t i o n / No p r o t e c t i o n . 4. Number o f l a n e s . 5. W i d t h o f l a n e s . 6. E x t r a w i d t h f o r c u r b s , g u t t e r s and s i d e w a l k s . 7. T o t a l r i g h t o f way w i d t h n e c e s s a r y f o r d e s i g n . 8. E x t r a r i g h t o f way w i d t h n e c e s s a r y beyond e x i s t i n g 100 f o o t r i g h t o f way. 9. S a f e t y w a l l s needed? How many? I t i s n e c e s s a r y t o j u s t i f y t h e d e s i g n f e a t u r e s o f each o f t h e a r c h e t y p e s and t h e c o n t r o l . The r a t i o n a l i z a t i o n f o r t h e s e d e s i g n s i s d e r i v e d from: 1. P r i n c i p l e s o f n o i s e a t t e n u a t i o n and b a r r i e r e f f e c t i v e n e s s f o u n d i n a v a i l a b l e r e s e a r c h . 2. C h a r a c t e r i s t i c s p a r t i c u l a r to t h e case s t u d y s i t u a t i o n ( t h e s e w i l l be d i s c u s s e d i n S e c t i o n 2 o f t h i s c h a p t e r and i n C h a p t e r 5, S e c t i o n 3 ) . The f i r s t d e s i g n , the C o n t r o l , i s an example o f a roadway c r o s s s e c t i o n w h i c h w o u l d be employed i f no b a r r i e r s were c o n s t r u c t e d . I t i s e s s e n t i a l i n the c o m p a r a t i v e a n a l y s i s as g r o s s n o i s e l e v e l s ( l e v e l s w i t h o u t b a r r i e r a t t e n u a t i o n ) can be d e t e r m i n e d f r o m t h i s d e s i g n . F u r t h e r , c o s t s , a e s t h e t i c s and c i r c u l a t i o n f e a t u r e s can be compared w i t h r e s p e c t t o t h e C o n t r o l d e s i g n . W i t h r e s p e c t t o the t o t a l h e i g h t o f each a r c h e t y p e b a r r i e r i t i s i m p r a c t i c a l t o compare d e s i g n s w i t h d r a s t i c a l l y d i f f e r e n t changes i n e l e v a t i o n . A b r e a k i n t h e l i n e o f s i g h t f r o m the s o u r c e t o t h e r e c e i v e r i s FIGURE 9: CONTROL 1, NO BARRIER CONFIGURATION 78 i r 3' >2' /Z' /Z' /Z' /Z' ?' FIGURE 10: ARCHETYPE 2, VERTICAL RETAINED WALLS 7S /Z' • / i ' / 2 ' iZ — i 1 r 3' /Z' ,Z' 3' FIGURE 11: ARCHETYPE 3, EARTH SLOPE < i fZ' /z' /"'Z.4- I 1 | - Y It' 3' lZ' tZ' 3' I 30. FIGURE 12: ARCHETYPE 4, BERM FIGURE 13: ARCHTEYPE 5, COMBINATION EARTH SLOPE-BERM FIGURE 14: ARCHETYPE 6, COMBINATION EARTH SLOPE-BERM (WITH FULL PROTECTION) TABLE 7: COMPARISON OF ARCHETYPES AND CHARACTERISTICS ARCHETYPES CHARACTERISTICS TOTAL VERTICAL HEIGHT OF BARRIER HEIGHT OF FENCES FULL PROTECTION (6 LANES)/ PARTIAL PROTECTION (2 LANES)/ NO PROTECTION NUMBER OF LANES WIDTH OF LANES EXTRA WIDTH FOR CURBS, GUTTERS AND SIDEWALK TOTAL RIGHT OF WAY WIDTH NECESSARY FOR DESIGN EXTRA R.O.W. WIDTH NECESSARY BEYOND EXISTING 100 FT. R.O.W. SAFETY WALLS NEEDED? HOW MANY? CONTROL 1 (NO PROTECTION) 0' 0' NO PROTECTION 6 12' 20' 98' 0' NO ARCHETYPE .2 (DEPRESSED THROUGH LANES WITH VERTICAL RETAINED WALLS) 18' 6' PARTIAL . PROTECTION 6 12' 20' 98' 0' YES, 2 ARCHETYPE 3 (DEPRESSED THROUGH LANES WITH EARTH SLOPE WALLS) 18' 6» PARTIAL PROTECTION 6 12' 20' 134' 34' YES, 2 ARCHETYPE 4 (BERMS) 18' 6' FULL PROT. 6 12' 20' 170' 70' NO ARCHETYPE 5 (COMBINA-TION EARTH SLOPE DEPRESSION WITH BERMS) 21' 6' PARTIAL PROTECTION 6 12' 20' 170' 70' NO ARCHETYPE 6 (COMBINA-TION EARTH SLOPE DEPRESSION WITH BERMS - FULL PROTECTION) 21* 6' FULL PROTECTION 6 12' 20' 170' 70' YES,. 2 : 32. t h e g u i d i n g p r i n c i p l e d e t e r m i n i n g t h e n o i s e a t t e n u a t i o n e f f e c t o f a b a r r i e r . (See A p p e n d i x 1, F i g u r e B-7.) T h e r e f o r e i t i s r e l a t i v e l y p o i n t l e s s t o compare a d e s i g n w i t h 6 f o o t change i n e l e v a t i o n t o one w i t h a 25 f o o t change i n e l e v a t i o n . The l a t t e r d e s i g n w i l l c e r t a i n l y be more e f f e c t i v e . C o n s i d e r i n g t h i s f a c t t h e a r c h e t y p e s a r e d e s i g n e d w i t h 12 f o o t ( d e s i g n s 2, 3 and 4) and 15 f o o t ( d e s i g n s 5 and 6) changes i n e l e v a t i o n . Each c o n f i g u r a -t i o n employs a 6 f o o t f e n c e ; t h e r e f o r e the t o t a l h e i g h t o f the b a r r i e r i s e i t h e r 18 f e e t ( d e s i g n s 3, 4 and 5) o r 21 f e e t ( d e s i g n s 5 and 6 ) . These h e i g h t s a r e c o n s i d e r a b l y h i g h e r t h a n b a r r i e r s t e s t e d i n most p r e v i o u s r e s e a r c h c o n s u l t e d . (1) The a d d i t i o n a l h e i g h t i s n e c e s s a r y t o compensate f o r t he h i g h e r p e r c e n t a g e s o f t r u c k t r a f f i c and t h e r e f o r e t h e h i g h e r a p p a r e n t n o i s e s o u r c e f a c t o r . F u r t h e r , one s t u d y f o u n d t h a t b a r r i e r s the h e i g h t o f 8 t o 10 f e e t were e s s e n t i a l l y i n e f f e c t i v e i n freeway s i t u a t i o n s . (2) A l l o f t h e a r c h e t y p e s employ 6 f o o t f e n c e s . These a r e used i n o r d e r t o e x t e n d the e f f e c t i v e b a r r i e r h e i g h t w i t h o u t h a v i n g t o e x t e n d t h e r i g h t o f way w i d t h (as w o u l d be t h e case i n berm o r e a r t h s l o p e d e s i g n s ) o r e x c a v a t e and b u i l d h i g h e r r e t a i n e d w a l l s ( A r c h e t y p e 2 ) . H i g h e r f e n c e s a r e n o t employed because t h e y w o u l d be v i s u a l l y i n t r u s i v e . One s t u d y f o u n d t h a t f e n c e s o r w a l l s 10 f e e t o r h i g h e r were c o n s i d e r e d a e s t h e t i c a l l y u n d e s i r a b l e . (3) I n a d d i t i o n , most m u n i c i p a l i t i e s have b y l a w s r e s t r i c t i n g t he h e i g h t s o f f e n c e s . I n t h e D i s t r i c t o f C o q u i t l a m a r e s t r i c t i o n o f 4 f e e t f o r f e n c e s f r o n t i n g s t r e e t s and 8 f e e t f o r s i d e y a r d f e n c e s e x i s t s . (4) C o n s i d e r i n g t h e s e f a c t s , 6 f e e t i s chosen as an a p p r o p r i a t e h e i g h t f o r f e n c e s . A r c h e t y p e 2 employs a v e r t i c a l r e t a i n e d w a l l , a common t r a f f i c b a r r i e r d e s i g n . (5) The e s s e n t i a l p o s i t i v e c h a r a c t e r i s t i c o f t h i s d e s i g n i s t h a t t h e b a r r i e r i s v e r y c l o s e t o t h e h i g h n o i s e g e n e r a t i n g s o u r c e o f the t r u c k t r a f f i c . The most e f f e c t i v e b a r r i e r s , a p a r t f r o m h e i g h t , a r e t h o s e c l o s e s t t o t h e r e c e i v e r . (6) A t r a d e - o f f i s made i n A r c h e t y p e 2 i n t h a t a l t h o u g h 33. t h e b a r r i e r i s c l o s e t o t h e h i g h n o i s e g e n e r a t i n g t r u c k t r a f f i c i t p r o v i d e s no p r o t e c t i o n f o r t h e on-grade l o c a l t r a f f i c . The r e a s o n s the cut does n o t c o n t a i n a l l s i x l a n e s a r e : 1. The b a r r i e r s w o u l d be f a r t h e r away and t h e r e f o r e l e s s e f f e c t i v e w i t h r e s p e c t t o t h r o u g h t r u c k t r a f f i c . 2. L o c a l c i r c u l a t i o n i s c o m p l i c a t e d because l o c a l t r a f f i c l a n e s a r e n o t on-grade. 3. The e x t r a expense f o r a d d i t i o n a l e x c a v a t i o n . A r c h e t y p e 3 i s i d e n t i c a l t o 2 b u t employs e a r t h s l o p e w a l l s r a t h e r t h a n v e r t i c a l r e t a i n e d ones. The q u e s t i o n w h i c h w i l l be answered by i n t r o d u c i n g t h i s d e s i g n i s , "How much l e s s e f f e c t i v e i s t h i s b a r r i e r due t o i t s g r e a t e r d i s t a n c e f r o m the t r u c k t r a f f i c ? " . F u r t h e r i t i s h y p o t h e s i z e d t h a t c o n s t r u c -t i o n c o s t s w i l l be l o w e r due t o the e a r t h s l o p e d e s i g n w h i c h i s c heaper t h a n the r e t a i n e d w a l l t y p e . However, due t o t h e e x t r a r i g h t o f way needed e x t r a l a n d c o s t s w i l l be i n c u r r e d . I f i t i s o n l y n e g l i g i b l y l e s s e f f e c t i v e t h a n A r c h e t y p e 2 i n n o i s e a t t e n u a t i o n , how does i t s t a c k up w i t h r e s p e c t t o a e s t h e t i c s , c i r c u l a t i o n and c o s t ? A r c h e t y p e 4 i s a s i m p l e on-grade berm d e s i g n . Berms a r e a p o p u l a r t y p e o f t r a f f i c n o i s e b a r r i e r o f t e n r e f e r r e d t o i n r e s e a r c h t e s t i n g (7) and employed i n t h e Vancouver a r e a . (8) I n t h i s s t u d y the berms p r o v i d e s i x l a n e p r o t e c t i o n b u t the b a r r i e r s a r e n o t as c l o s e t o the t r u c k t r a f f i c as i n A r c h e t y p e s 2 and 3. A r c h e t y p e s 5 and 6, the c o m b i n a t i o n e a r t h s l o p e - berm d e s i g n s , a r e i d e n t i c a l e x c e p t t h a t 5 p r o v i d e s t h r o u g h l a n e p r o t e c t i o n and 6 p r o v i d e s s i x l a n e p r o t e c t i o n . These two d e s i g n s e n a b l e a c o m p a r i s o n between b a r r i e r s w i t h f u l l p r o t e c t i o n and t h o s e p r o v i d i n g p r o t e c t i o n c l o s e t o t h e h i g h n o i s e g e n e r a t i n g t r u c k t r a f f i c . There a r e two f u r t h e r j u s t i f i c a t i o n s f o r t e s t i n g t h i s type o f d e s i g n . One i s s u g g e s t e d i n a s t u d y w h i c h was e s s e n t i a l l y 34. c o n c e r n e d w i t h t e s t i n g f e n c e - t y p e b a r r i e r s s i t u a t i o n s . The most e f f e c t i v e s e c t i o n appears t o be a c u t s e c t i o n w i t h e a r t h embankment o r o t h e r b a r r i e r on t h e c r e s t . (9) The s e c o n d j u s t i f i c a t i o n i s t h a t i n b o t h A r c h e t y p e s 5 and 6 t h e f i l l m a t e r i a l f o r the berms r o u g h l y e q u a l s the e x c a v a t e d m a t e r i a l f r o m t h e d e p r e s s e d p o r t i o n s . These d e s i g n s s h o u l d be c h e a p e r i n t h a t l a r g e amounts o f m a t e r i a l do n o t have t o be t r u c k e d i n o r away from the s i t e as i s the case i n a l l the o t h e r a r c h e t y p e s . F u r t h e r c o n s t r u c t i o n f a c t o r s d e t e r m i n e c h a r a c t e r i s t i c s o f t h e d e s i g n s : 1. A l l s l o p e s i n the e a r t h s l o p e and berm d e s i g n s ( A r c h e t y p e s 3, 4, 5 and 6) a r e 1:1.5 ( r i s e t o r u n ) . T h i s i s because s l o p e s g r e a t e r than t h i s w o u l d e n t a i l c o s t l y s l o p e s t a b i l i z a t i o n c o n s t r u c t i o n . 2. Wooden f e n c e s a r e employed r a t h e r t h a n c o n c r e t e w a l l s . T h i s i s due t o a e s t h e t i c and c o s t r e a s o n s e x p l a i n e d i n C h a p t e r 5, S e c t i o n 2, and C h a p t e r 6, S e c t i o n 1. 3. C o n c r e t e s a f e t y w a l l s , 2 f e e t h i g h , a r e n e c e s s a r y i n A r c h e t y p e s 2, 3 and 6. I f t h e s e w a l l s were n o t used t r a f f i c c o u l d d a n g e r o u s l y swerve o v e r embankments. I t i s c o n c l u d e d t h e r e i s sound t h e o r e t i c a l j u s t i f i c a t i o n f o r t h e a r c h e t y p e s s e l e c t e d . The f o l l o w i n g f a c t o r s were c o n s i d e r e d i n d e v e l o p i n g the d e s i g n s : 1. N o i s e a t t e n u a t i o n p r i n c i p l e s . 2. A e s t h e t i c p r i n c i p l e s . 3. C i r c u l a t i o n f a c t o r s o f t h e case s t u d y s i t u a t i o n . 4. C o n s t r u c t i o n f a c t o r s . 5. C o s t . 3.2 DESCRIPTION OF THE CASE STUDY The D i s t r i c t o f C o q u i t l a m i s w i t h i n the n o r t h e a s t s e c t o r o f t h e G r e a t e r 35. Vancouver R e g i o n a l D i s t r i c t (see F i g u r e 1 5 ) . The p o p u l a t i o n o f t h i s s e c t o r p r e s e n t l y (1976) i s about 100,000, about o n e - t w e l f t h o f the t o t a l G.V.R.D. p o p u l a t i o n , b u t e x p e c t e d t o i n c r e a s e by 1986 t o o v e r 150,000. (10) I n a d d i t i o n t o C o q u i t l a m ' s r o l e as a r e s i d e n t i a l suburb o f Vancouver, i t accommodates c o n s i d e r a b l e i n d u s t r i a l a c t i v i t y i n c l u d i n g the e x t r a c t i o n o f g r a v e l from p i t s a l o n g the C o q u i t l a m R i v e r . The case s t u d y s i t u a t i o n e v o l v e s a r o u n d t h e e x p e c t e d c o n f l i c t between g r a v e l t r u c k t r a f f i c coming from the C o q u i t l a m R i v e r a r e a ( P i p e l i n e Road) and the p r o p o s e d C o q u i t l a m C e n t r e A r e a development (see F i g u r e 1 6 ) . T h i s s e c t i o n w i l l p r o c e e d t o d e s c r i b e t h e b a s i c f e a t u r e s o f t h e s e two e l e m e n t s , t h e town c e n t r e and f u t u r e g r a v e l e x t r a c t i o n w h i c h w i l l d i c t a t e p o t e n t i a l volumes o f t r u c k t r a f f i c . I m p o r t a n t i n the d e s c r i p t i o n i n r e s p e c t t o t h i s s t u d y a r e t h e l a n d use t y p e s f l a n k i n g the roadway and t h e f o r e c a s t e d volumes o f t r u c k s and c a r s . ( T a r g e t n o i s e s t a n d a r d s v a r y w i t h l a n d use t y p e s and g r o s s n o i s e l e v e l s depend i n p a r t on volumes o f t r u c k s and c a r s . ) I n 1974 t h e G r e a t e r Vancouver R e g i o n a l D i s t r i c t (G.V.R.D.) i n t r o d u c e d p o l i c i e s aimed a t d e c e n t r a l i z i n g t h e c o m m e r c i a l , V a n c o u v e r - c e n t r e d , c o r e and d e v e l o p i n g s m a l l e r d i s p e r s e d c o m m e r c i a l c e n t e r s . (11) E s s e n t i a l l y , i n re s p o n s e t o t h i s r e g i o n a l p o l i c y and a d e s i r e t o b r o a d e n i t s c o m m e r c i a l p r o p e r t y t a x base t h e D i s t r i c t o f C o q u i t l a m began d e v e l o p i n g a p l a n f o r t h e " C o q u i t l a m C e n t r e A r e a " . I n March 1976 a r e l a t e d " N o r t h C o q u i t l a m P l a n " was p r e s e n t e d a t a p u b l i c m e e t i n g , and has s i n c e been a d o p t e d by C o q u i t l a m C o u n c i l . The e s s e n t i a l f e a t u r e s o f t h e p l a n a r e : . 150 a c r e Town C e n t r e a r e a i n c l u d i n g : 1.3 m i l l i o n s q . f t . o f r e t a i l s pace 1.5 m i l l i o n s q . f t . o f o f f i c e space 0.9 m i l l i o n s q . f t . o f c u l t u r a l , i n s t i t u t i o n a l and g o v e r n m e n t a l s p a c e ; . 300 a c r e s o f c o m m e r c i a l and l i g h t i n d u s t r i a l space w i t h i n a d e s i g n a t e d t r a n s p o r t a t i o n and s e r v i c e c o r r i d o r ; . 200 a c r e s o f l a n d f o r medium and h i g h - d e n s i t y h o u s i n g i n a n a t u r a l s e t t i n g and i n t e g r a t e d w i t h t h e n a t u r a l l a n d s c a p e ; 36. l o c a t i o n o f pro p o s e d C o q u i t l a m c e n t r e development FIGURE 15:- GREATER VANCOUVER REGIONAL DISTRICT ' MAP ILLUSTRATES FOUR PROPOSED G.V.R.D REGIONAL TOWN CENTRES (INCLUDING COQUITLAM TOWN CENTRE DEVELOPMENT) AND THE CONNECTING TRANSPORTATION CORRIDORS. i 38. . c o n v e n t i o n a l l o w - d e n s i t y r e s i d e n t i a l a r e a s a d j o i n i n g h i g h e r d e n s i t y a r e a s and i n t e g r a t e d w i t h t h e n a t u r a l l a n d s c a p e ; . l a r g e a r e a s o f p a r k s and r e c r e a t i o n a l f a c i l i t i e s c o n n e c t i n g the C o q u i t l a m R i v e r w i t h a l a k e i n the p r o p o s e d Town C e n t r e A r e a ; . a p p r o x i m a t e l y 15,000 j o b o p p o r t u n i t i e s as a d v o c a t e d by t h e d e c e n t r a l i z i n g p o l i c i e s o f t h e G.V.R.D.; . a new community co r e a r e a c o m f o r t a b l y accommodating 50,000 p e o p l e i n manner c o n s i s t e n t w i t h community g o a l s ; . b a l a n c e d and c o m p a t i b l e use o f l a n d r e s p e c t i n g e n v i r o n m e n t a l r e q u i r e m e n t s . (12) S i n c e March 19 76 t h e C o q u i t l a m P l a n n i n g and E n g i n e e r i n g Departments .have "endeavoured t o draw up more s p e c i f i c programs d i r e c t e d at the s p e c i f i c p o l i c i e s . A l a n d use map was c o m p l e t e d i n September 19 76 (see F i g u r e 16) w h i c h r e v e a l s the p e r t i n e n t l a n d uses f l a n k i n g the case s t u d y r o u t e ( a p p r o x i -m a t e l y one m i l e o f P i n e Tree Way). These l a n d uses a r e : 1. l o w - d e n s i t y a p a r t m e n t ; 2. p a r k and open s p a c e ; 3. s c h o o l ; 4. c i v i c ; 5. i n t e n s i v e c o m m e r c i a l . The case s t u d y r o u t e b e g i n s ( t h e n o r t h end) where P i n e Tree Way makes a r i g h t a n g l e t u r n . (See F i g u r e 1 6 ) . I t i s a t t h i s p o i n t where b o t h p a r k and low-d e n s i t y apartment l a n d uses f l a n k t h e roadway. A t the s o u t h e r n end o f t h e r o u t e t h e f l a n k i n g l a n d use changes from i n t e n s i v e t o e x t e n s i v e c o m m e r c i a l . I t i s thought w i t h e x t e n s i v e c o m m e r c i a l s u c h as l a r g e s h o p p i n g m a l l s , d e s i g n arrangements c o u l d be made ( i . e . p u t p a r k i n g n e x t t o roadway and s e t back b u i l d i n g s ) t o r e n d e r b a r r i e r d e s i g n , a l t e r n a t i v e s u n n e c e s s a r y . A l t h o u g h the l a n d use d e l i n e a t i o n s a r e o n l y t e n t a t i v e a t t h e p r e s e n t s t a g e o f p l a n n i n g (1977) t h e y w i l l be t r e a t e d as i f e s t a b l i s h e d . Some p a r t i c u l a r f e a t u r e s n o t r e v e a l e d on t h e l a n d use map a r e w o r t h y o f m e n t i o n . One p r e d i c t e d use i n the c i v i c a r e a i s a c e n t e r f o r p e r f o r m i n g a r t s . A t t e n t i o n w i l l have t o be p a i d towards n o i s e l e v e l s i f t h i s c e n t e r i s e s t a b l i s h e d . F u r t h e r a t t e n t i o n w i l l have t o be p a i d t o n o i s e l e v e l s i n the i n t e n s i v e 3 9 . c o m m e r c i a l a r e a as i t i s a n t i c i p a t e d r e s i d e n t i a l accommodation w i l l be i n t e g r a t e d w i t h s m a l l s c a l e shops and o f f i c e s . I n a d d i t i o n , h o t e l accommo-d a t i o n w i l l be p r o v i d e d . I t i s the hope o f t h e C o q u i t l a m p l a n n e r s t o e s t a b l i s h an i n t e g r a t e d employment, s h o p p i n g , r e c r e a t i o n a l and r e s i d e n t i a l community. F o r t h i s r e a s o n t h e d i v e r s e l a n d uses a r e i n c l o s e p r o x i m i t y , p r o v i d i n g t h e e s s e n t i a l e l e m e n t s o f an i n d e p e n d e n t community w h i c h does n o t have t o r e l y on commuting t o e x i s t . C o n s i d e r a b l e p e d e s t r i a n and o u t d o o r a c t i v i t y i s e x p e c t e d (note t h e p a r k and s c h o o l a r e s ) , e m p h a s i z i n g a g a i n t h e need f o r an e n v i r o n m e n t f r e e f r o m unwanted t r a f f i c n o i s e . W i t h t h e s e l a n d use c h a r a c t e r i s t i c s i n mind t h e somewhat c o n f l i c t i n g f u t u r e o f g r a v e l e x t r a c t i o n a c t i v i t y i s now c o n s i d e r e d . G r a v e l e x t r a c t i o n has e x i s t e d i n the C o q u i t l a m a r e a f o r o v e r 20 y e a r s and c o n f l i c t s between t r u c k e r s and i r a t e c i t i z e n s have, been f r e q u e n t . I n f a c t t h e p r e s e n t r o u t e t h e t r u c k s t a k e , P i n e T r e e Way, was b u i l t i n s p i t e o f c o n s i d e r a b l e c i t i z e n p r o t e s t . R e s i d e n t s b o r d e r i n g the s o u t h e r n end o f P i p e l i n e Road o b j e c t e d t o the new r o u t e w h i c h w o u l d b i s e c t a q u i e t , s c e n i c p a r k . However, a f t e r a l e n g t h y d e l a y and even c o u r t a c t i o n the r o u t e was a u t h o r i z e d by the C o q u i t l a m M u n i c i p a l C o u n c i l . (13) W i t h r e s p e c t t o the Town C e n t r e p r o p o s a l p o l i t i c i a n s and p l a n n e r s seem to have r e j e c t e d a new r e r o u t i n g s o l u t i o n because i t i s th o u g h t t h i s w o u l d o n l y t r a n s f e r t h e t r u c k t r a f f i c v e r s u s c i t i z e n s c o n f l i c t e l s e w h e r e and n o t e l i m i n a t e i t . (14) E v i d e n c e o f t h e D i s t r i c t ' s c o n c e r n about the c o n f l i c t and i n t e r e s t i n the v i a b i l i t y o f d e s i g n s o l u t i o n s i s r e v e a l e d i n t h e P o l i c y Report No. 2/76, September 1976: Recommendations ... 9. That t h e P l a n n i n g Department, i n c o n j u n c t i o n w i t h t h e E n g i n e e r i n g Department, r e v i e w the m a t t e r o f a d e s i g n s o l u t i o n f o r g r a v e l t r u c k s i n t h e p r o p o s e d c o r e a r e a , p o s s i b l y i n v o l v i n g grade s e p a r a t i o n . (15) 40. P r e s e n t volumes o f d a i l y t r u c k t r a f f i c on P i n e T r e e Way were c a l c u l a t e d f o r t h e D i s t r i c t by McElhanney and A s s o c i a t e s , E n g i n e e r i n g C o n s u l t a n t s , by means o f a c t u a l t r u c k t r a f f i c counts c o n d u c t e d on June 17 and 18, 1976. These f i g u r e s were p r e s e n t e d i n the P o l i c y R e p o r t No. 2/76 w h i c h was a d o p t e d by C o q u i t l a m C o u n c i l . G r a v e l t r u c k s now number some 1300 i n one d i r e c t i o n on P i n e t r e e Way o r 65% o f the t o t a l 2000 v e h i c l e s ... (16) However, the d i f f i c u l t y l i e s i n p r e d i c t i n g what f u t u r e volumes m i g h t be. The f o l l o w i n g somewhat c o n f l i c t i n g f o r c e s w i l l d etermine what t h e s e volumes w i l l be: 1. C o n t r a c t o r s c o n t a c t e d i n the a r e a i n t e n d t o i n c r e a s e t h e i r p r o d u c t i o n o u t p u t . F u r t h e r t h e y c l a i m economic f o r c e s w i l l make C o q u i t l a m R i v e r g r a v e l r e l a t i v e l y more v a l u a b l e i n t h e f u t u r e as demand i n c r e a s e s and s u p p l i e s c l o s e t o t h e urban a r e a s a r e d e p l e t e d . (There i s a t l e a s t 20 y e a r s more e x p e c t e d l i f e i n C o q u i t l a m R i v e r p i t s , u s i n g the h i g h e s t a n n u a l e x t r a c t i o n f i g u r e s . ) F u r t h e r , C o q u i t l a m p i t s are among the c l o s e s t t o the h i g h consuming r e g i o n s u r r o u n d i n g Vancouver. 2. The D i s t r i c t o f C o q u i t l a m can d i r e c t l y c o n t r o l t h e amount o f g r a v e l e x t r a c t e d f r o m w i t h i n i t s b o u n d a r i e s by means o f i t s S o i l Removal Bylaw, and can t h e r e f o r e c o n t r o l the volumes o f t r u c k t r a f f i c . L a t e s t i n d i c a t i o n s are t h a t i t w o u l d l i k e t o r e z o n e some g r a v e l p i t l a n d s b e c a u s e o f t h e supposed d e t r i m e n t a l e f f e c t s i l t f r o m the p i t s has on salmon spawning beds i n t h e C o q u i t l a m R i v e r , whether t h e D i s t r i c t w i s h e s t o cut back e x t r a c t i o n a c t i v i t y i s a n o t h e r i s s u e . T h i s i s because i t c o l l e c t s a l u c r a t i v e f e e t h r o u g h i t s S o i l Removal Bylaw. T h i s f e e ($0.20 p e r c u b i c y a r d ) amounted t o a p p r o x i m a t e l y $270,000 i n 1975 and $300,000 i n 1976. I t i s d o u b t f u l t h e D i s t r i c t o f C o q u i t l a m w o u l d l i k e t o see t h i s revenue d e c r e a s e o r d i s a p p e a r . Due t o t h e above f a c t o r s and t h e g e n e r a l u n c e r t a i n t y about t h e t i m i n g o f f u t u r e development i n t h e a r e a , i t i s i m p o s s i b l e t o p i c k a p o i n t i n the f u t u r e and make an a b s o l u t e judgement about t h e volumes o f t r u c k s and c a r s e x p e c t e d . F u r t h e r m o r e i t i s beyond t h e scope o f t h i s s t u d y t o make a d e t a i l e d a n a l y s i s i n t h i s a r e a . However, i n o r d e r t o make some judgement about t h e n o i s e a t t e n u a t i o n c a p a b i l i t i e s o f t h e f i v e a r c h e t y p e s some v e h i c l e volumes must be employed. I t w i l l be assumed, f o r t h e sake o f t h i s s t u d y , t h a t because t h e D i s t r i c t i s i n t e r e s t e d i n p u r s u i n g d e s i g n a l t e r n a t i v e s i t i s c o n t e m p l a t i n g t h e v i a b i l i t y o f c o n t i n u i n g e x t r a c t i o n a c t i v i t y . T h i s p o l i c y w o u l d c o r r e s p o n d t o t h e d e s i r e s o f t h e c o n t r a c t o r s and t h e s u p p l y and demand s i t u a t i o n p r e v i o u s l y d i s c u s s e d . The D i s t r i c t ' s p o s i t i o n and t r a f f i c f o r e c a s t s a r e c o n t a i n e d i n t h e P o l i c y R e p o r t No. 2/76: ... i n t h e l o n g e r t e r m , some 11,000 v e h i c l e s p e r day (one way) are f o r e s e e n , o f w h i c h 5,000 r e l a t e t o the C o q u i t l a m C e n t r e development and up t o 1,500 p e r day b e i n g g r a v e l t r u c k s . (17) 1,500 t r u c k s p e r day (3,000 two way) i s 15 p e r c e n t more t h a n i s p r e s e n t l y e x p e r i e n c e d on P i n e t r e e Way on an average w o r k i n g day, c a l c u l a t e d on an a n n u a l b a s i s . The f i g u r e s q u o t e d above a r e the r e s u l t o f p r e d i c t i o n s s u b m i t t e d t o C o q u i t l a m P l a n n i n g Department f r o m t r a f f i c e n g i n e e r i n g c o n s u l t a n t s P. R oer and Z. Kuun t o g e t h e r w i t h McElhanney and A s s o c i a t e s . They w i l l be employed i n t h e p r e s e n t s t u d y w h i c h w i l l c o n s i d e r two way t r a f f i c as i s n e c e s s a r y f o r n o i s e l e v e l p r e d i c t i o n . The f o l l o w i n g two way v e h i c l e t r i p s p e r w o r k i n g day f i g u r e s w i l l be used: 22,000 v e h i c l e s p e r day c o m p r i s e d o f 3,000 t r u c k s and 19,000 c a r s . The P o l i c y R e p o r t i n d i c a t e s 10,000 (two way) v e h i c l e s r e l a t e d t o t h e C o q u i t l a m C e n t r e development. These w i l l be c o n s i d e r e d l o c a l t r a f f i c w h i c h w i l l n o t use t h e t h r o u g h l a n e s o f t h e a r c h e t y p e d e s i g n s . I t w i l l be assumed t h e r e m a i n i n g 9,000 two way v e h i c l e s and t h e 3,000 two way g r a v e l t r u c k s 42. w i l l use the t h r o u g h l a n e s , as n e i t h e r a r e r e l a t e d t o the C e n t r e development. I t must be e m p h a s i z e d t h a t even i f t h e e s t i m a t e s u s e d h e r e do n o t c o r r e s p o n d t o what i n f a c t w i l l be t h e a c t u a l volumes, o r do n o t c o r r e s p o n d t o e s t i m a t e s made a t a f u t u r e date when f e w e r u n c e r t a i n t i e s e x i s t , the r e s t o f t h e methodology i s u n a f f e c t e d . T h a t i s , t h e b a r r i e r d e s i g n s , t h e n o i s e p r e d i c t i o n model, a t t e n u a t i o n e f f e c t and o t h e r c r i t e r i a ( c o s t , a e s t h e t i c s and c i r c u l a t i o n ) r e m a i n r e l e v a n t and c o u l d be used i n c o n j u n c t i o n w i t h d i f f e r e n t t r a f f i c volume p r e d i c t i o n s . 4 3 . FOOTNOTES 1. See M. H a r m e l i n k and J . H a j e k , " N o i s e B a r r i e r E v a l u a t i o n and A l t e r n a t i v e s f o r Highway N o i s e C o n t r o l " , M. T.C. R e p o r t , No. RR180, 1972. 2. i b i d . , p. 8. 3. J . L . Be a t o n and L. B o u r g e t , "Can N o i s e R a d i a t i o n f r o m Highways be Reduced D e s i g n " , Highway R e s e a r c h B o a r d 232, 1968. 4. R e v e a l e d by L. W o l f , D i s t r i c t o f C o q u i t l a m P l a n n i n g Department. 5. See D. M a r s h a l l , A Minimum Community Impact Urban Freeway, t h e s i s f o r th e S c h o o l o f Community and R e g i o n a l P l a n n i n g , U.B.C., 1976. 6. C o n s i d e r i n g two b a r r i e r s o f i d e n t i c a l h e i g h t , t h e one c l o s e s t t o t h e n o i s e s o u r c e w i l l have a h i g h e r e f f e c t i v e h e i g h t . 7. M. H a r m e l i n k and J . H a j e k , c>p_. c i t . 8. Two examples o f berms i n t h e Vancouver a r e a a r e a t Southwest M a r i n e D r i v e and G r a n v i l l e S t r e e t and between t h e F a l s e Creek Redevelopment P r o j e c t and 5 t h Avenue. 9. M. H a r m e l i n k and J . Hajek, c>p_. c i t . , pp. 13-14. 10. G r e a t e r Vancouver R e g i o n a l D i s t r i c t , The L i v a b l e R e g i o n 1976-1986, 1975, p. 2. 11. i b i d . , p. 8. 12. D i s t r i c t o f C o q u i t l a m , The Community P l a n f o r t h e C o q u i t l a m C e n t r e A r e a , P o l i c y R e p o r t No. 2/76, September 1976, pp. 1-2. 13. The Vancouver Sun, June 11, 1971. 14. R e v e a l e d i n d i s c u s s i o n s w i t h L. W o l f , C o q u i t l a m P l a n n i n g Department, and P. Roer, C o n s u l t i n g T r a f f i c E n g i n e e r f o r C o q u i t l a m C e n t r e A r e a P l a n . 15. D i s t r i c t o f C o q u i t l a m , op_. c i t . , p. 7. • 16. i b i d . , p. 2. 17. i b i d . , p. 2. 44. CHAPTER 4: NOISE ATTENUATION EFFECT OF THE FIVE ARCHETYPES  4.1 INTRODUCTION The prime concern of this chapter is the application of the Ontario Highway Noise Prediction Method to the Coquitlam case study. Before consider-ing the noise prediction model, pertinent variables must be discussed. The Ontario model considers vehicle flow in hourly increments. In Chapter 3 volumes were calculated in terms of average volumes per working day per year. This of course implies on many days the volumes w i l l be higher as this is just ari average figure. It i s thought that protection should be introduced for peak hour per average working day t r a f f i c but not for what might be the peak hour per year. Volumes at this level are too infrequent to be considered. (In the same sense using the L ^ Q level ignores the 10% higher than acceptable noise emissions.) Peak volumes per day are calculated using the standard 10% of daily volume method. (1) That i s , to determine average daily peak hour flow the average daily flow is divided by 10. Therefore in the case study situation the average peak hour flow for a l l vehicles is 2,200 (10% of 22,000). Vehicle speed i s another variable which must be determined. Speed.; limits in most urban arterials in the Vancouver region are restricted to 30 m.p.h. However, actual speeds are often slightly higher than posted ones. It is thought that posted speeds i n the order of 40-50 m.p.h. would not be practical due to the local circulation and pedestrian activity. Further as i t is a major objective to lower noise levels and noise levels increase with speed and flow variability, i t i s contradictory to encourage higher speeds. Enforced speeds lower than 35 m.p.h. would be inappropriate in the case of trucks because they would likely be changing gears at less than cruising speeds. The changing of gears creates the essential noise factor up to 30 to 40 m.p.h. Beyond 30 to 40 m.p.h. speed becomes, more 45. i m p o r t a n t as t h e r e i s a s u b s t a n t i a l i n c r e a s e i n n o i s e f r o m t i r e - r o a d i n t e r a c t i o n . (2) T h e r e f o r e the a v e r a g e s p e e d f o r case s t u d y w i l l be c o n s i d e r e d 35 m.p.h. (The O n t a r i o M o d e l i n c o r p o r a t e s an a d j u s t m e n t f o r i n t e r r u p t e d v e h i c l e f l o w w h i c h w i l l be employed as c o n s t a n t v e h i c l e speeds a r e n o t e x p e c t e d . See A p p e n d i x 1, Step 4.7.) R e p r e s e n t a t i v e d i s t a n c e s from the roadway have t o be d e t e r m i n e d . H o r i z o n t a l d i s t a n c e s from t h e edge o f t h e roadway ( o r i n A r c h e t y p e s 4 and 6 from the edge o f t h e berms) o f 25 f e e t and 50 f e e t a re s e l e c t e d . 25 f e e t r e p r e s e n t s the p e d e s t r i a n and open sp a c e a c t i v i t y w h i l e 50 f e e t r e p r e s e n t s t h e c l o s e s t e x p e c t e d d i s t a n c e f o r s t r u c t u r e s . Measurements a t 25 f e e t a r e c a l c u l a t e d from 4 f e e t above grade (a s t a n d a r d h e i g h t i n n o i s e measurement r e s e a r c h ) and a t 50 l a t e r a l f e e t , a t h e i g h t s o f 4, 10, 20, 30 and 40 f e e t . 10, 20, 30, and 40 f e e t r e p r e s e n t c a l c u l a t i o n s i n t h e f i r s t f o u r f l o o r s o f s t r u c t u r e s . The 50 f o o t d i s t a n c e f r o m t h e edge o f t h e roadway o r b a r r i e r s t r u c t u r e i s d e r i v e d f r o m t h e D i s t r i c t o f C o q u i t l a m ' s Z o n i n g Bylaw (3) w h i c h s t i p u l a t e s t h a t c o m m e r c i a l and r e s i d e n t i a l s e t b a c k s f r o m f r o n t l o t l i n e s on a r t e r i a l s cannot be l e s s t h a n 37 f e e t . Add t o t h i s t h e a d d i t i o n a l 10 f e e t (on each s i d e o f t h e roadway) f o r c u r b s , g u t t e r s and s i d e w a l k s the minimum d i s t a n c e f r o m t h e roadway edge a b u i l d i n g c o u l d be i s 47 f e e t - c o r r e s p o n d i n g t o t h e 50 f o o t c r i t e r i o n used h e r e . Measurements a t e l e v a t i o n s g r e a t e r t h a n 40 f e e t above grade were n o t r e c o r d e d because a t t h i s h e i g h t none o f t h e d e s i g n s a r e e f f e c t i v e . I f b u i l d i n g s a r e h i g h e r than 40 f e e t a t a d i s t a n c e o f 50 f e e t from the roadway edge c o n s i d e r a t i o n o f a r c h i t e c t u r a l a c o u s t i c c o n t r o l may be n e c e s s a r y . The f o l l o w i n g s e c t i o n o f t h i s c h a p t e r d i s c u s s e s how the g e n e r a l " P r o c e d u r e F o r P r e d i c t i o n o f Highway N o i s e U s i n g t h e O n t a r i o Method" (Appendix 1) i s a p p l i e d t o t h e case s t u d y . A p p e n d i x 2 g i v e s the r e s u l t s o f the a p p l i c a t i o n i n c l u d i n g g r o s s n o i s e l e v e l s , a t t e n u a t i o n e f f e c t o f 46. b a r r i e r s and r e s u l t a n t .noise . l e v e l s a t a l l the c r i t i c a l l a t e r a l and v e r t i -c a l d i s t a n c e s . ( I n r e s p e c t t o t h e r e s u l t s t h e f o l l o w i n g n o t a t i o n s y s t e m i s used. (25,4) means 25 l a t e r a l f e e t and 4 v e r t i c a l f e e t , (50,4) means 50 l a t e r a l f e e t and 4 v e r t i c a l f e e t , and so on.) 4.2 APPLICATION OF THE ONTARIO NOISE PREDICTION MODEL (See B/ D e t a i l e d P r o c e d u r e i n A p p e n d i x 1.) STEP 1 Determine t h e p e r c e n t i l e o f t h e d e s i r e d s ound l e v e l (L ^ Q > O R ^5) • As d i s c u s s e d i n C h a p t e r 2, the L ^ Q l e v e l has been s e l e c t e d . STEP 2 D i v i d e t he highway i n t o s e c t i o n s . A s t r a i g h t s t r e t c h o f highway w i l l be c o n s i d e r e d w i t h no i n t e r v e n i n g s t r u c t u r e s o t h e r than the i n t e n d e d b a r r i e r s . The f o l l o w i n g c r i t e r i a a r e c o n s t a n t : a. c a r and t r u c k f l o w (1,900 c a r s and 300 t r u c k s p e r h o u r ) ; b. t r a f f i c f l o w s p e e d (35 m.p.h.) and t r a f f i c f l o w c h a r a c t e r i s t i c s ( a and b a r e c o n s i d e r e d c o n s t a n t w i t h i n t h e s i n g l e h y p o t h e t i c a l e l e ment a l t h o u g h an a d j u s t m e n t o f +2.5 dBA i s a p p l i e d t o t r u c k r e l a t e d n o i s e l e v e l s c a l c u l a t e d t o compensate f o r e x p e c t e d i n t e r r u p t e d f l o w ) ; c. pavement s u r f a c e t y p e ( t h e r e i s no r e a s o n t o b e l i e v e t h e pavement s u r f a c e t y p e w i l l v a r y ) ; d. highway g r a d i e n t ( a l t h o u g h t h e r e a r e s l i g h t changes i n g r a d i e n t a l o n g t h e case s t u d y r o u t e , t he h y p o t h e t i c a l elements w i l l be o f c o n s i s t e n t g r a d e ) ; e. b r e a k i n the l i n e o f s i g h t between the highway n o i s e s o u r c e and the o b s e r v e r ' s p o s i t i o n ( w i t h i n each 1 A r c h e t y p e d e s i g n t h e b a r r i e r h e i g h t r emains c o n s t a n t ; t h e r e f o r e t h e b r e a k i n the l i n e o f s i g h t i s c o n s t a n t ) . STEP 3 U s i n g t h e nomograph f o r L - n p e r c e n t i l e l e v e l i n A p p e n d i x 1, sound 47. l e v e l s emitted were calculated f o r each element at the given representative l a t e r a l and v e r t i c a l l o c a t i o n s . Control 1 and Archetype 4 each contain one element. Archetype 6 contains three elements. Archetypes 2, 3, and 5 contain two elements. (In 2, 3, and 5 i f Sound l e v e l s are calculated as i f the r e c e i v e r i s on the r i g h t hand side of the roadway cross s e c t i o n the sound emitted from the l e f t hand element i s n e g l i g i b l e because i t passes through two b a r r i e r s ; therefore these Archetypes are considered to have only two elements.) Diagrams i l l u s t r a t i n g the elements of each archetype are presented on the following two pages. D i f f e r e n t gross noise l e v e l s are found depending on the archetype i n question. This i s because the various designs employ d i f f e r e n t r i g h t of way widths ( i . e . the berm designs are wider than the v e r t i c a l or earth-slope designs). Consequently noise l e v e l s are lower.with the berm designs even without considering the r e l a t i v e attenuation e f f e c t of the b a r r i e r . (Recall that sound, l e v e l s are reduced by approximately 4.5 dBA with every doubling of distance from the source.) However, as a guideline the Control 1 gross noise l e v e l s are pertinent and these are presented i n Table 8. TABLE 8 GROSS NOISE LEVELS OF.THE CONTROL DESIGN WITH 1, 2, AND 3 ELEMENT CALCULATIONS (CONTROL 1 has s i x 12-foot lanes on grade with no b a r r i e r configuration.) ( A l l noise l e v e l c a l c u l a t i o n s >below are ±2.5 dBA.) COORDINATES (25,4) (50,4) (50,10) (50,20 (50,30) (50,40) 2 ELEMENT NOISE CALCULATION 78.1 75.0 75.0 75.0 75.0 75.0 3 ELEMENT NjOISE CALCULATION 76. 7 73.7 73.7 73.7 73.7 73.7 1 ELEMENT NOISE CALCULATION 79.5 76.0 76.0 76.0 76.0 76.0 ELEMENTS OF THE ARCHETYPES (RECEIVER TO THE LEFT OF DIAGRAMS) FIGURE 17: ELEMENTS IN CONTROL 1 48. 78 FIGURE 18: ELEMENTS IN ARCHETYPE 2 7S tZ' /a' 7 ST £x-£>i£rv-r J J IZ iZ ' ro FIGURE 19: ELEMENTS IN ARCHETYPE 3 IZ' /Z' «0 '— 49. FIGURE 20: ELEMENTS IN ARCHETYPE 4 FIGURE 21: ELEMENTS IN ARCHETYPE 5 FIGURE 22: ELEMENTS IN ARCHETYPE 6 /So' C a l c u l a t i n g n o i s e l e v e l s as i f th e y a r e e m i t t e d f r o m 2 and 3 e l e m e n t s u n d e r p r e d i c t s t h e c a l c u l a t i o n made from one e l e m e n t . The above t a b l e i l l u s t r a t e s t h a t u s i n g t h e l o g a r i t h m i c t a b l e p r e s e n t e d i n C h a p t e r 2, one w i l l u n d e r p r e d i c t i n t h e o r d e r o f 1.2 dBA when two el e m e n t s a r e c o n s i d e r e d and i n the o r d e r o f 2.5 dBA when t h r e e e l e m e n t s a r e c o n s i d e r e d . T h e r e f o r e upward a d j u s t m e n t s o f 1.2 and 2.5 dBA a r e a p p l i e d t o a l l n o i s e c a l c u l a t i o n s r e s u l t i n g from the l o g a r i t h m i c a d d i t i o n s o f two o r t h r e e e l e m e n t s . STEP 4 Fo r each element t h e f o l l o w i n g a d j u s t m e n t s were a p p l i e d t o sound l e v e l s o b t a i n e d i n Step 3: a. A d j u s t m e n t f o r E l e m e n t S i z e . Each element c o n s i d e r e d i s t h e o r e t i c a l l y o f i n f i n i t e l e n g t h ; t h e r e f o r e no a d j u s t m e n t i s made f o r e l e m e n t s i z e . I f the h y p o t h e t i c a l e l e m e n t s c o n t a i n e d s h a r p bends ( i n t h e roadway) o r i n t e r -v e n i n g s t r u c t u r e s ( o t h e r than t h e i n t e n d e d b a r r i e r s ) t h i s a d j u s t m e n t w o u l d be n e c e s s a r y . b. A d j u s t m e n t f o r S h i e l d i n g E f f e c t o f N a t u r a l and A r t i f i c i a l B a r r i e r s ( I n c l u d i n g D e p r e s s e d and E l e v a t e d Highway S e c t i o n s ) . A p p l y i n g the f o r m u l a f o r b a r r i e r a t t e n u a t i o n as d e s c r i b e d i n A p p e n d i x 1, S e c t i o n 4.1, b a r r i e r a t t e n u a t i o n r e s u l t s were o b t a i n e d . The complete r e s u l t s a r e f o u n d i n A p p e n d i x 2. The s h i e l d i n g e f f e c t o f b a r r i e r s r a n g e d f r o m 19 dBA a t c o o r d i n a t e (25,4) and (50,4) i n A r c h e t y p e 5, el e m e n t 2, t o 0 dBA i n a number o f c a l c u l a t i o n s where t h e s i g h t l i n e between s o u r c e and r e c e i v e r was n o t b r o k e n . The c r u c i a l a p p a r e n t h e i g h t o f the n o i s e s o u r c e , u s i n g the t a b l e B-2 i n A p p e n d i x 1, v a r i e d from 1 f o o t t o 9 f e e t a c c o r d i n g t o t h e p e r c e n t a g e o f t r u c k t r a f f i c . As d i s c u s s e d i n C h a p t e r 3, i t i s assumed t h a t a l l g r a v e l t r u c k s w i l l t r a v e l i n the t h r o u g h (most p r o t e c t e d ) l a n e s . I n ele m e n t s c o n t a i n i n g o n l y l o c a l ( C e n t r e development) t r a f f i c t h e a p p a r e n t h e i g h t was assumed t o be 1 f o o t . 51. The d i s t a n c e away from t h e n o i s e s o u r c e i s n o t c a l c u l a t e d by t h e f o r m u l a p r e s e n t e d i n A p p e n d i x 1, S e c t i o n 4.2, b u t by t h e " p s e u d o - l a n e " f o r m u l a i n t r o d u c e d by G a l l o w a y e t a l . and employed by M a r s h a l l . M a r s h a l l , i n A M i n i m a l Community Impact Urban Freeway, s t a t e s : The p s e u d o - l a n e i s a h y p o t h e t i c a l s i n g l e l a n e t o w h i c h a l l t r a f f i c (and c o n s e q u e n t l y t h e o r i g i n o f a l l n o i s e ) i s summarized. ' T h i s s i n g l e - l a n e - e q u i v a l e n t can be c o n s i d e r e d as a h y p o t h e t i c a l l a n e c a r r y i n g t h e t o t a l f l o w ( i g n o r i n g t h e o v e r l a p o f r e a l v e h i c l e s ) . I t s h o u l d be c o n s i d e r e d as l o c a t e d at a p o s i t i o n d i s p l a c e d f r o m t h e c l o s e s t l a n e t o t h e o b s e r v e r by a d i s t a n c e e q u a l t o t h e s q u a r e r o o t o f t h e number o f l a n e s t i m e s t h e l a n e w i d t h . F o r example, on a f o u r -l a n e highway the e f f e c t i v e p s e u d o - l a n e w o u l d be a t t h e l o c a t i o n o f the s e c o n d l a n e c l o s e s t t o t h e o b s e r v e r . ' (4) c. A d j u s t m e n t f o r Highway G r a d i e n t . The change i n grade o v e r t h e case r o u t e i s l e s s t h a n two p e r c e n t ; t h e r e f o r e no a d j u s t m e n t i s n e c e s s a r y i n t h i s r e s p e c t . d. A d j u s t m e n t f o r Pavement S u r f a c e Type. I t i s assumed t h a t t h e pavement s u r f a c e t y p e i s n o r m a l w i t h no r e s u l t i n g d e c i b e l a d j u s t m e n t . S e a l - c o a t e d and rough a s p h a l t pavements a r e uncommon on w e l l - t r a v e l l e d a r t e r i a l r o u t e s as i s t h e case h e r e . e. and f . Ad j u s t m e n t f o r S h i e l d i n g E f f e c t Due t o V e g e t a t i o n and Houses. There i s no a d j u s t m e n t made f o r t h e s e f a c t o r s . Any v e g e t a t i o n w i t h i n 50 f e e t o f t h e roadway w o u l d p r o v i d e o n l y n e g l i g i b l e a t t e n u a t i o n e f f e c t a c c o r d i n g t o A p p e n d i x 1, S e c t i o n 4.5. No houses a r e e x p e c t e d t o be l o c a t e d w i t h i n 50 f e e t o f t h e roadway. g. A d j u s t m e n t f o r I n t e r r u p t e d Flow. An a d j u s t m e n t o f 2-3 dBA i s recommended f o r i n t e r r u p t e d t r a f f i c f l o w c o n t a i n i n g a t l e a s t 60 heavy t r u c k s p e r h o u r . An a d j u s t m e n t o f +2.5 dBA i s employed i n t h i s c a s e . h. A d j u s t m e n t f o r Ground A t t e n u a t i o n . No a d j u s t m e n t i s c o n s i d e r e d as t h e recommended a d j u s t m e n t r e f e r s t o e x p a n s i v e a r e a s o f g r a s s l a n d a t l e a s t 100 f e e t w i d e . 52. STEP 5 F o r each e l e m e n t a d j u s t m e n t s a re a r i t h m e t i c a l l y added t o sound l e v e l s c a l c u l a t e d i n Step 3. STEP 6 L o g a r i t h m i c a l l y , sound l e v e l s f r o m d i f f e r e n t e l e m e n t s a r e added. T h i s i s done by means o f t h e t a b l e , " A d d i t i o n o f Sound L e v e l s " , p r e s e n t e d i n C h a p t e r 2. 4.3 COMPARISON OF THE EFFECT OF BARRIERS TO TARGET STANDARDS Ta b l e 9 r e v e a l s t h e n o i s e l e v e l s w i t h t h e e f f e c t o f b a r r i e r s c a l c u l a t e d u s i n g t h e O n t a r i o N o i s e P r e d i c t i o n Method a t d i s t a n c e s o f 25 f e e t and 50 f e e t f r o m t h e edge o f t h e roadway o r berm and a t e l e v a t i o n s o f 4, 10, 20, 30 and 40 f e e t . TABLE 9 CALCULATED NOISE LEVELS IN dBA L 1 0 FOR CONTROL, AND 5 ARCHETYPES ( A l l l e v e l s ±2.5 dBA) RECEIVER COORDINATES (25,4) (50,4) (50,10) (50,20) (50,30) (50,40) CONTROL 1 - NO BARRIERS 79.5 76.0 76.0 76.0 76.0 76.0 ARCHETYPE 2 - VERTICAL RETAINED 72.8 66.6 66.7 6 7,0 67.5 68.4 ARCHETYPE 3 - EARTH SLOPE 71.5 66.8 67.3 67.8 72.1 72.1 ARCHETYPE 4 - BERM 62.5 59.0 61.0 64.0 66.0 76.0 ARCHETYPE 5 - COMBINATION EARTH SLOPE/BERM 71.2 66.4 66.5 66.8 67.3 68.2 ARCHETYPE 6 - COMBINATION EARTH SLOPE/BERM (FULL PROTECTION) 56.6 56.7 58.9 62.9 71.5 71.5 A r c h e t y p e 2 p r o v i d e s good p r o t e c t i o n a t a l l c a l c u l a t i o n s 50 f e e t f r o m t h e road's edge. ( A l l f i g u r e s are w i t h i n 2.5 o f 65 dBA e x c e p t (50,40).) 53. However, a t 25 f e e t t h e l e v e l o f 72.8 I s c o n s i d e r a b l y h i g h e r . T h i s l e v e l i s due p r i m a r i l y t o t h e u n p r o t e c t e d s e c o n d e l e m e n t ( t h e one c l o s e s t t o t h e r e c e i v e r ) . None o f t h e c a l c u l a t e d l e v e l s meet t h e 58 ± 2.5 s t a n d a r d a p p l i e d t o p a r k use. A r c h e t y p e 3 p r o v i d e s s i m i l a r r e s u l t s t o t h o s e o f A r c h e t y p e 2. However, a t 50 l a t e r a l f e e t and a t e l e v a t i o n s o f 30 and 40 f e e t no s h i e l d i n g e f f e c t i s f e l t . T h i s i s because t h e b a r r i e r i n A r c h e t y p e 3, t h e e a r t h s l o p e , i s f a r t h e r away f r o m t h e s o u r c e t h a n i s t h e v e r t i c a l w a l l b a r r i e r i n A r c h e t y p e 2. C o n s e q u e n t l y the " e f f e c t i v e h e i g h t " of t h e A r c h e t y p e 3 b a r r i e r i s l o w e r . A g a i n due t o t h e u n p r o t e c t e d s e c o n d element a h i g h e r n o i s e l e v e l , 71.5 dBA, i s a l s o c a l c u l a t e d a t 25 f e e t from t h e road's edge. A r c h e t y p e 4 p r o v i d e s c o n s i d e r a b l y b e t t e r p r o t e c t i o n a t p o i n t s ( 2 5 , 4 ) , ( 5 0 , 4 ) , ( 5 0 , 1 0 ) , (50,20) and (50,30) due t o the f a c t t h a t t h e e n t i r e v e h i c l e f l o w i s s h i e l d e d from the r e c e i v e r . T h i s i s n o t t h e case i n A r c h e t y p e s 2 and 3. However, a t (50,40) where t h e s i g h t l i n e i s unbroken, t h e l e v e l d r a s t i c a l l y i n c r e a s e s t o 76.0 dBA. E x c e p t f o r t h e p a r k c r i t e r i o n o f 58 ± 2.5 at (25,4) and a t p o i n t ( 5 0 , 4 0 ) , t h i s d e s i g n s a t i s f i e s the t a r g e t s t a n d a r d s . A r c h e t y p e 5 p r o v i d e s a l m o s t i d e n t i c a l p r o t e c t i o n t o t h a t o f A r c h e t y p e 2. The t a r g e t s t a n d a r d i s o b t a i n e d e x c e p t f o r t h e p a r k c r i t e r i o n o f 58 ± 2.5. A g a i n due t o the u n p r o t e c t e d l o c a l t r a f f i c element c l o s e s t t o t h e r e c e i v e r h i g h l e v e l s a r e c a l c u l a t e d a t (25,4) - 71.2 dBA. A r c h e t y p e 6 p r o v i d e s t h e b e s t p r o t e c t i o n o f a l l at c o o r d i n a t e s ( 2 5 , 4 ) , ( 5 0 , 4 ) , (50,10) and (50,20) - 56.6, 56.7, 58.9, and 62.9 dBA r e s p e c t i v e l y . These l e v e l s s u i t b o t h the P a r k use and the o t h e r l a n d use t a r g e t s t a n d a r d s . A g a i n , however, a t e l e v a t i o n s o f 30 and 40 f e e t l e s s p r o t e c t i o n i s f e l t -71.5 dBA. C o n s i d e r a t i o n o f t h e a t t e n u a t i o n e f f e c t o f a l l the A r c h e t y p e s i n a c o m p a r a t i v e f a s h i o n i s g i v e n i n the t a b l e s 10 and 11. I f t h e c a l c u l a t i o n w i t h b a r r i e r p r o t e c t i o n i s w i t h i n +2.5 dBA o f t h e t a r g e t s t a n d a r d p r o t e c t i o n i s c o n s i d e r e d "good". I f the c a l c u l a t i o n i s w i t h i n +5 dBA p r o t e c t i o n i s c o n s i d e r e d " a d e q u a t e " , and i f t h e c a l c u l a t i o n i s g r e a t e r t h a n 5 dBA h i g h e r p r o t e c t i o n i s c o n s i d e r e d " i n a d e q u a t e " . T h i s d e l i n e a t i o n i s b a s e d on t h e 2.5 dBA a c c u r a c y o f t h e measurements u s i n g t h e O n t a r i o N o i s e P r e d i c t i o n Method and t h e speech i n t e r f e r e n c e c r i t e r i a as d e f i n e d i n C h a p t e r 2, S e c t i o n 3. T a b l e 5 shows d i s t i n c t i v e d i f f e r e n c e s i n l e v e l s o f speech n e c e s s a r y w i t h r e s p e c t t o 10 dBA i n c r e m e n t s i n t r a f f i c n o i s e . U s i n g the +5 dBA l e v e l t o i n d i c a t e t h e d i f f e r e n c e between adequate and i n a d e q u a t e speech communication s u g g e s t s t h a t w i t h r e s p e c t t o t h e 65 dBA t a r g e t s t a n d a r d , o u t d o o r speech communication i s adequate when t r a f f i c n o i s e l e v e l s a r e f r o m +2.5 t o +5 dBA o f 65 dBA, b u t i n a d e q u a t e when t r a f f i c n o i s e l e v e l s a r e w i t h i n 5 dBA o f 75 dBA. ( W i t h n o i s e l e v e l s o f 75 dBA one must speak i n a r a i s e d v o i c e a t 1-2 f e e t f r o m the r e c e i v e r f o r n o r m a l speech communication.) The f i r s t t a b l e c o n s i d e r s p r o t e c t i o n o f t h e b a r r i e r c o n f i g u r a t i o n s i n r e s p e c t t o t h e low d e n s i t y a p a r t m e n t , c o m m e r c i a l , c i v i c and s c h o o l t a r g e t s t a n d a r d o f 65 ± 2.5 dBA. The s e c o n d t a b l e c o n s i d e r s p r o t e c t i o n o f t h e b a r r i e r c o n f i g u r a t i o n s i n r e s p e c t t o t h e p a r k t a r g e t s t a n d a r d o f 58 ± 2.5. Recommendations about w h i c h a r c h e t y p e s a r e a p p r o p r i a t e can o n l y be done a f t e r c o n s i d e r i n g t h e a e s t h e t i c , c i r c u l a t i o n and c o s t f a c t o r s w h i c h w i l l be done i n the f o l l o w i n g two c h a p t e r s . G e n e r a l l y s p e a k i n g , however, t h e r e s u l t s o f t h e a t t e n u a t i o n e f f e c t o f the 5 b a r r i e r a r c h e t y p e s a r e e n c o u r a g i n g . A l l d e s i g n s show c o n s i d e r a b l e improvement o v e r c o n d i t i o n s w i t h o u t any s h i e l d i n g e f f e c t . R e f e r r i n g t o the r e s u l t s r e v e a l e d i n t a b l e s 10 and 11, a l l o f the a r c h e t y p e s p e r f o r m e d w e l l a t c o o r d i n a t e s ( 5 0 , 4 ) , (50,10) and ( 5 0 , 2 0 ) . 55. COMPARISON OF THE 5 ARCHETYPES IN RESPECT TO THE LAND USE TARGET STANDARDS Key f o r Tables 10 and 11: * = "good" protection (within +2.5 of 65 dBA) / = "adequate" protection (within +5.0 of 65 dBA) x = "inadequate" protection (above +5.0 of 65 dBA). TABLE 10 j COMPARISON OF ARCHETYPES WITH 65 ± 2.5 TARGET STANDARD ARCHETYPE DESCRIPTION RECEIVER COORDINATES (25,4) (50,4) ,(50,10) • (50,20) • (50,30) • (50,40) 1. CONTROL (NO PROTECTION) X X X X X X 2. VERTICAL/RETAINED X * * * A / 3. EARTH SLOPE X * * * X X 4. BERM * * * * A X 5. COMBINATION EARTH SLOPE-BERM X * * * A / 6. COMBINATION EARTH SLOPE-BERM (FULL PROTECTION) * * * * X X TABLE 11 COMPARISON OF ARCHETYPES WITH 58 ± 2.5 TARGET STANDARD . ARCHETYPE DESCRIPTION RECEIVER COORDINATES (25,4) (50,4) (50,10) (50,20) (50,30) (50,40) 1. CONTROL (NO PROTECTION)v X x X No te: Coordinates (50,20), (50,30), (50,40) are not considered i n respect to the park target standard of 58 ± 2.5 dBA because heights from 20'- 40'above grade are not expected at roadside i n the park area. 2. VERTICAL/RETAINED X X X 3. EARTH SLOPE X X X 4. BERM • / * / 5. COMBINATION EARTH SLOPE-BERM X • X X 6. COMBINATION EARTH SLOPE-BERM.(FULL PROTECTION A * * The d i s t i n g u i s h i n g d i f f e r e n c e among the a r c h e t y p e s i s fo u n d i n the p e r f o r -mance l e v e l s a t c o o r d i n a t e s ( 2 5 , 4 ) , (50,30) and ( 5 0 , 4 0 ) . A r c h e t y p e s 2 and 5 p e r f o r m e d w e l l a t t h e (50,30) c o o r d i n a t e and a d e q u a t e l y a t t h e (50,40) p o i n t . A r c h e t y p e s 4 and 6 p e r f o r m e d w e l l i n r e s p e c t t o t h e 65 ± 2.5 t a r g e t s t a n d a r d a t p o i n t s (25,4) and (50,4) b u t c o n s i d e r i n g the p a r k s t a n d a r d o f 58 ± 2.5 o n l y one A r c h e t y p e , 6, p e r f o r m e d w e l l a t c o o r d i n a t e s (25,4) and ( 5 0 , 4 ) . 57. FOOTNOTES 1. R e v e a l e d by P. Roer and Z. Kuun, T r a f f i c E n g i n e e r s f o r the C o q u i t l a m C e n t r e A r e a P l a n , as a s t a n d a r d method used i n p r e d i c t i n g peak h o u r t r a f f i c volumes. 2. W.H. C l o s e and T. A t k i n s o n , " T e c h n i c a l B a s i s f o r M o t o r C a r r i e r and R a i l r o a d N o i s e R e g u l a t i o n s " , Sound and V i b r a t i o n , O c t o b e r 1973, p. 29. 3. D i s t r i c t o f C o q u i t l a m , Z o n i n g Bylaw No. 1928, 1971, S e c t i o n 703 ( 1 ) , (c) . 4. D. M a r s h a l l , A M i n i m a l Community Impact Urban Freeway, t h e s i s f o r the S c h o o l o f Community and R e g i o n a l P l a n n i n g , U.B.C., 1976, p. 55. M a r s h a l l q u o t e s W. G a l l o w a y e t a l . , Highway N o i s e : Measurement,  S i m u l a t i o n and M i x e d R e a c t i o n s , NCHRP R e p o r t 78, 1969, p. 13. 58. CHAPTER 5: EVALUATION OF THE ARCHETYPES WITH RESPECT TO AESTHETICS  AND CIRCULATION 5.1 INTRODUCTION A e s t h e t i c s and c i r c u l a t i o n a r e u s u a l l y n o t c o n s i d e r e d i n t r a f f i c n o i s e b a r r i e r s t u d i e s . N o i s e a t t e n u a t i o n i s e i t h e r i s o l a t e d as t h e o n l y c o n c e r n o f the s t u d y o r a p p a r e n t l y c o n s i d e r e d o v e r w h e l m i n g l y more i m p o r t a n t t h a n a e s t h e t i c s and c i r c u l a t i o n . I t must be k e p t i n mind, however, t h a t b e c a u s e most a t t e n u a t i o n s t u d i e s r e f e r p r e d o m i n a n t l y t o highway c o n d i t i o n s , c i r c u l a t i o n i s u s u a l l y c o n s i d e r e d b e f o r e t h e need f o r b a r r i e r s i s f e l t . That i s , b a r r i e r s p l a c e d on e x i s t i n g highway c o n f i g u r a t i o n s a r e n o t con--s i d e r e d i n r e s p e c t t o i n t e r s e c t i o n and o v e r p a s s s e c t i o n s . F u r t h e r , t h e r e i s n o t t h e c o n c e r n f o r p e d e s t r i a n s a f e t y and ease o f c i r c u l a t i o n as i s the case i n t h i s s t u d y . The r e s u l t o f t h i s l a c k o f e x i s t i n g i n f o r m a t i o n on a e s t h e t i c s and c i r c u l a t i o n i s t h a t c r i t e r i a f o r a n a l y s i s and comparison must be d e v e l o p e d l a r g e l y i n an i n t u i t i v e f a s h i o n . 5.2 AESTHETIC EVALUATION One s t u d y c o n s i d e r e d w h i c h does a c c o u n t f o r a e s t h e t i c s i n b a r r i e r e v a l u a t i o n i s D. M a r s h a l l ' s A M i n i m a l Community Impact Urban Freeway. The f o l l o w i n g q u e s t i o n s a r e a d d r e s s e d i n r e s p e c t t o v i s u a l i n t r u s i o n : 1. I s the highway s t r u c t u r e u n s i g h t l y i t s e l f ? 2. Does i t b l o c k s i g n i f i c a n t v i e w s ? 3. Does i t a f f o r d v i e w s i n t o a d j a c e n t r e s i d e n t i a l p r o p e r t y ? (1) M a r s h a l l ' s d e s i g n s a l l i n v o l v e d e p r e s s e d highways and he c o n c l u d e s t h a t none o f t h e above f a c t o r s a r e n e g a t i v e l y a f f e c t e d by t h e s e s t r u c t u r e s . (2) C o n s i d e r i n g the t h r e e q u e s t i o n s i n r e s p e c t t o t h e f i v e a r c h e t y p e s , somewhat s i m i l a r c o n c l u s i o n s can be drawn. I t i s t h o u g h t t h a t none o f t h e f i v e a r c h e t y p e s can be c o n s i d e r e d any more u n s i g h t l y t h a n t h e C o n t r o l 59. s i t u a t i o n . I n f a c t , t h e berm d e s i g n s must be c o n s i d e r e d an a e s t h e t i c " p l u s " . E x t r a p o l a t i n g f r o m t h e q u e s t i o n o f " u n s i g h t l i n e s s " , one can j u d g e t h e f i v e a r c h e t y p e s i n r e s p e c t t o how many v e h i c l e s a r e v i s i b l e f r o m s t r e e t l e v e l . Assuming " t h e more v e h i c l e s one sees t h e more u n s i g h t l y t h e s i t u a t i o n " , the f o l l o w i n g comparison can be made: TABLE 12 COMPARISON OF NUMBERS OF VEHICLES VISIBLE FROM STREET LEVEL WITH RESPECT TO FIVE ARCHETYPES AND CONTROL ARCHETYPE DESCRIPTION VEHICLE V I S I B I L I T Y VALUE* CONTROL 1 NO BARRIERS ALL VEHICLES VISIBLE 0 ARCHETYPE 2 VERTICAL RETAINED LOCAL VEHICLES VISIBLE 1 ARCHETYPE 3 EARTH SLOPE LOCAL VEHICLES VISIBLE 1 ARCHETYPE 4 BERM NO VEHICLES VISIBLE 2 ARCHETYPE 5 COMBINATION BERM/EARTH SLOPE LOCAL VEHICLES VISIBLE 1 ARCHETYPE 6 COMBINATION BERM/EARTH SLOPE (FULL PROTECTION) NO VEHICLES VISIBLE 2 * The h i g h e r the v a l u e t h e more p o s i t i v e the a e s t h e t i c e f f e c t i n r e s p e c t t o v e h i c l e v i s i b i l i t y . C o n s i d e r i n g M a r s h a l l ' s s e c o n d q u e s t i o n , "Does i t b l o c k s i g n i f i c a n t v i e w s ? " , i t i s thought none o f t h e A r c h e t y p e s f a i l i n t h i s c a t e g o r y . T h i s i s because s i g n i f i c a n t v i e w s ( i . e . m o u n t a i n s , panoramas, e t c . ) w o u l d be seen from above berm s t r u c t u r e s o r i f one i s v e r y c l o s e t o a berm, o t h e r s t r u c t u r e s such as r e s i d e n t i a l o r c o m m e r c i a l b u i l d i n g s w o u l d l i k e l y b l o c k one's v i e w anyway. I n t h e case o f t h e p a r k a r e a where no h i g h b u i l d i n g s 60. a r e e x p e c t e d , s i g n i f i c a n t v i e w s m i g h t be b l o c k e d i f one i s v e r y c l o s e t o th e berm. However, e x c e p t f o r t h i s one s p e c i f i c s i t u a t i o n no a r c h e t y p e s can be c o n s i d e r e d as " b l o c k i n g s i g n i f i c a n t v i e w s " . M a r s h a l l ' s t h i r d c r i t e r i o n , "Does i t a f f o r d v i e w s i n t o a d j a c e n t r e s i d e n t i a l p r o p e r t y ? " , can r e s u l t i n a s i m i l a r c o m p a r i s o n as t h a t p r e s e n t e d i n t h e above t a b l e . A l t h o u g h none o f t h e a r c h e t y p e s p r o v i d e a v i e w " b e t t e r " t h a n one w o u l d have from t h e C o n t r o l s i t u a t i o n , some b l o c k t h e v i e w f r o m more p a s s i n g m o t o r i s t s t h a n o t h e r s . The r e l a t i v e v a l u e s one c o u l d e x p e c t i n r e s p e c t t o each o f t h e a r c h e t y p e s i s i d e n t i c a l t o tho s e on t h e p r e v i o u s t a b l e . C o n s i d e r i n g t h e v i e w t h e m o t o r i s t has from t h e r o a d one a s s u m p t i o n i s made. I n r e s p e c t t o the two c e n t e r l a n e s a more e x p a n s i v e v i e w o f t h e r o a d s i d e i s p r e f e r a b l e t o a t u n n e l - l i k e v i e w c r e a t e d by b a r r i e r s t r u c t u r e s c l o s e t o t h e m o t o r i s t . I n t h i s r e s p e c t A r c h e t y p e 2 i s t h e l e a s t p r e f e r a b l e . The o t h e r d e s i g n s a f f o r d v a r y i n g degrees o f v i s i b i l i t y b u t A r c h e t y p e 2 i s o b v i o u s l y f a r l e s s d e s i r a b l e from the m o t o r i s t ' s p o i n t o f v i e w . There a r e a number o f a e s t h e t i c q u a l i t i e s o f t h e d e s i g n s w h i c h a r e s i m i l a r and t h e r e f o r e don't a f f o r d a c o m p a r a t i v e judgement, b u t n o n e t h e l e s s a r e s t i l l w o r t h y o f me n t i o n . I t i s t h o u g h t t h a t wooden f e n c e s a r e p r e f e r a b l e t o c o n c r e t e b l o c k s o r p o u r e d c o n r e t e w a l l s ( a l t h o u g h c o n c r e t e w a l l s c o u l d be c o v e r e d w i t h v e g e t a t i o n t h e t o t a l c o s t s w o u l d be c o n s i d e r a b l y h i g h e r than t h e wood a l t e r n a t i v e - see C h a p t e r 6, s e c t i o n 1 ) . T h e r e f o r e wood i s employed a l t h o u g h s p e c i a l a t t e n t i o n has t o be p a i d t o minimum d e n s i t y , 4 l b . p e r s q u a r e f o o t , as any b a r r i e r m a t e r i a l w h i c h i s n o t t h i s dense p o s s e s s e s i n a d e q u a t e n o i s e a t t e n u a t i o n c a p a b i l i t i e s . (3) A l l o f t h e a r c h e t y p e s a r e c o n s i d e r e d more a e s t h e t i c a l l y p l e a s i n g than t h e C o n t r o l s i t u a t i o n . However, two d e s i g n s emerge as s l i g h t l y more p r e f e r a b l e . These are d e s i g n s 4 and 6. They " r a t e " s l i g h t l y h i g h e r i n 61. r e s p e c t t o the o b s e r v e r ' s v i e w o f v e h i c l e s and c o n g r u e n t l y t h e i r complete s h i e l d i n g o f t h e m o t o r i s t ' s v i e w o f p r i v a t e p r o p e r t y a d j a c e n t t o the r o a d -way. A r c h e t y p e 2 " r a t e s " l o w e r t h a n the o t h e r s i n r e s p e c t t o t h e " a n g l e o f v i s i b i l i t y " . One advantage A r c h e t y p e 6 may have o v e r 4 i s t h a t a l t h o u g h 6 has an a c t u a l b a r r i e r h e i g h t h i g h e r than 4 (21 f e e t v e r s u s 18 f e e t ) f r o m t h e o b s e r v e r ' s p o i n t o f view A r c h e t y p e 6 appears t o be l o w e r . FIGURE 23: ARCHETYPE 4, 18 FOOT APPARENT HEIGHT FIGURE 24: ARCHETYPE 6, 15 FOOT APPARENT HEIGHT I n A r c h e t y p e 6 t h e berm-fence c o m b i n a t i o n i s 15 f e e t above gr a d e ; i n A r c h e t y p e 4 i t i s 18 f e e t above grade. I t i s tho u g h t t h a t t h e l o w e r t h e berm-f e n c e s t r u c t u r e t he l e s s v i s u a l l y i n t r u s i v e t he d e s i g n i s t o t h e a d j a c e n t o b s e r v e r . S i m i l a r l y comparing A r c h e t y p e 3 t o 5, 3 h a v i n g the l o w e r a p p a r e n t h e i g h t would be c o n s i d e r e d more p r e f e r a b l e . D i f f e r e n t aesthetic c r i t e r i a have been introduced to' a f f o r d comparison of the various designs. However, to assign numerical values to these c r i t e r i a would be erroneous as there i s r e a l l y no means of quantifying the q u a l i t a t i v e judgements made. Some archetypes, though, do emerge as being more preferable than others i n an a e s t h e t i c sense. In terms of a quantitative a e s t h e t i c analysis the best that can be done here i s to rank the archetypes without' a c t u a l l y assigning values to the comparison. Based on the c r i t e r i a discussed here the 5 Archetypes and the Control s i t u a t i o n can be ranked i n the following fashion. TABLE 13 AESTHETIC PREFERABILITY OF FIVE ARCHETYPES ARCHETYPE' DESCRIPTION PREFERABILITY CONTROL 1 NO BARRIERS "LEAST PREFERABLE" ARCHETYPE 2 VERTICAL RETAINED 1 1 ARCHETYPE 5 COMBINATION EARTH SLOPE/BERM i ! ARCHETYPE 3 EARTH SLOPE i j ARCHETYPE 4 BERM i i ARCHETYPE 6 COMBINATION EARTH SLOPE/BERM (FULL PROTECTION)' "MOST PREFERABLE" •5.3 CIRCULATION EVALUATION In respect to c i r c u l a t i o n the 5 Archetypes possess c e r t a i n common features. 1. A l l have s i x lanes, which means they are equally able to handle t r a f f i c volumes i n respect to p o t e n t i a l capacity. (4) 2. A l l have or could have assigned through lanes f o r truck and commuter t r a f f i c . C o n s i d e r i n g the d i f f e r i n g c i r c u l a t i o n c h a r a c t e r i s t i c s A r c h e t y p e s 4 and 6 a r e n o t as e f f e c t i v e i n r e s p e c t t o l o c a l c i r c u l a t i o n as the o t h e r d e s i g n s and t h e C o n t r o l . I n C h a p t e r 3, S e c t i o n 3.1, w i t h i n t h e d e s c r i p t i o n s o f t h e a r c h e t y p e s i t was e x p l a i n e d t h a t l o c a l t r a f f i c w o u l d be d e s i g n a t e d t o o u t s i d e l a n e s i n d e s i g n s where o n l y t h r o u g h l a n e p r o t e c t i o n was p r o v i d e d . T h i s means t h a t i n a l l a r c h e t y p e s e x c e p t 4 and 6. l o c a l t r a f f i c can t u r n on and o f f l o c a l s t r e e t s w i t h o u t d i f f i c u l t y . I n A r c h e t y p e s 4 and 6 l o c a l l y c i r c u l a t i n g t r a f f i c i s b l o c k e d f r o m t u r n i n g by the berm s t r u c t u r e s . The berms can o f c o u r s e be t e r m i n a t e d a t each i n t e r s e c t i o n , b u t t h i s makes them f a r l e s s e f f e c t i v e as the s h i e l d i n g e f f e c t w o u l d o n l y be i n t e r m i t t e n t . T h e r e f o r e A r c h e t y p e s 2, 3 and 5 a r e b e t t e r s u i t e d t o l o c a l v e h i c l e c i r c u l a t i o n . (See sample i n t e r s e c t i o n d e s i g n s i n F i g u r e 25.) There w i l l have t o be a number o f p o i n t s a l o n g t h e one m i l e case s t u d y r o u t e where t r a f f i c can p a s s f r o m one s i d e o f t h e f a c i l i t y t o the o t h e r . I n t h e s e cases o v e r p a s s e s appear t o be e q u a l l y advantageous t o a l l a r c h e t y p e s . They w o u l d be n e c e s s a r y i n the d e p r e s s e d d e s i g n s and advan-tageous i n the berm d e s i g n s as berms w o u l d n o t have t o be b r o k e n t o a l l o w c r o s s f l o w i n g t r a f f i c t o p a s s . F u r t h e r , o v e r p a s s e s a l l o w t h e commuter and t r u c k t r a f f i c t o p a s s more q u i c k l y t h r o u g h t h e case s t u d y a r e a w i t h o u t b e i n g d e l a y e d by c r o s s f l o w i n g t r a f f i c on t h e same gra d e . R e f e r r i n g t o p e d e s t r i a n c i r c u l a t i o n , as o v e r p a s s e s have a l r e a d y b e e n s u g g e s t e d t h e y s h o u l d be d e s i g n e d t o accommodate p e d e s t r i a n s . F u r t h e r " p e d e s t r i a n o n l y " o v e r p a s s e s c o u l d be employed where heavy p e d e s t r i a n a c t i v i t y i s e x p e c t e d ( i . e . between the s c h o o l and t h e p a r k ) . I n t h i s r e s p e c t a l l a r c h e t y p e s appear t o be e q u a l l y advantageous. Those d e s i g n s w h i c h s e p a r a t e p e d e s t r i a n a c t i v i t y f r o m v e h i c l e c i r c u l a t i o n c o u l d be c o n s i d e r e d more advantageous f r o m a p e d e s t r i a n s a f e t y p o i n t o f v i e w . I n t h i s r e s p e c t d e s i g n s 4 and 6 a r e most advantageous 64. FIGURE 25: INTERSECTION DESIGNS FOR ARCHETYPES 2, 4, AND 6 65. as they i n c o r p o r a t e a berm between t h e o u t s i d e l a n e s and where t h e s i d e w a l k w o u l d be l o c a t e d . S u mmarizing t h e c i r c u l a t i o n a s p e c t s o f t h e a r c h e t y p e s , i t appears t h e r e i s no o v e r w h e l m i n g l y d i s t i n c t i v e advantage c o n t a i n e d w i t h i n any one o f t h e d e s i g n s . A r c h e t y p e s 4 and 6 a r e i n f e r i o r : i n r e s p e c t t o l o c a l c i r c u l a t i o n b u t s u p e r i o r i n r e s p e c t t o p e d e s t r i a n s a f e t y . 66. FOOTNOTES 1. D. M a r s h a l l , A M i n i m a l Community Impact Urban Freeway, t h e s i s f o r t h e S c h o o l o f Community and R e g i o n a l P l a n n i n g , U.B.C., 1976, p. 33. 2. i b i d . , p. 33. 3. M. H a r m e l i n k and J . H a j e k , " N o i s e B a r r i e r E v a l u a t i o n and A l t e r n a t i v e s f o r Highway N o i s e C o n t r o l " , M.T.C. R e p o r t , No. RR180, 1972, p. 2. 4. There i s a s l i g h t d i f f e r e n c e i f one c o n s i d e r s t h a t w e a v i n g i s r e s t r i c t e d i n a l l d e s i g n s e x c e p t t h e Berm A r c h e t y p e 4. Under c e r t a i n c o n d i t i o n s A r c h e t y p e 4 w i l l be a b l e t o h a n d l e h i g h e r volumes because i t a l l o w s l e s s r e s t r i c t e d w e a v i n g . 67. CHAPTER 6: COST EVALUATION OF THE ARCHETYPES  6.1 INTRODUCTION The l a s t v a r i a b l e w h i c h can be employed i n j u d g i n g t h e d i f f e r e n t a r c h e t y p e s i s c o s t . I n C h a p t e r 1, i t was s t a t e d c o s t s w o u l d be e x p r e s s e d i n 1977 d o l l a r s and n o r m a l i z e d t o a o n e - m i l e s t r e t c h o f roadway ( a p p r o x i -m a t e l y e q u a l t o the case s t u d y r o u t e l e n g t h ) . F u r t h e r , the c o s t s a r e s e p a r a t e d w i t h i n each d e s i g n a r c h e t y p e t o r e v e a l what a s p e c t s o f each i n c u r what c o s t s . The d e t e r m i n a t i o n o f u n i t c o s t s f o r c o n s t r u c t i o n o f d i f f e r e n t a s p e c t s o f d e s i g n s was done w i t h t h e h e l p o f J . H a f n e r , a p r o f e s s i o n a l e n g i n e e r and e s t i m a t o r f o r C o l u m b i a B i t u l i t h i c L t d . , a Vancouver b a s e d r o a d c o n s t r u c t i o n company. I t i s e s p e c i a l l y f o r t u n a t e t h a t h i s s e r v i c e s were a v a i l a b l e b ecause o f h i s p r e v i o u s e x p e r i e n c e w i t h e s t i m a t i n g and b u i l d i n g berm s t r u c t u r e s . F u r t h e r , he was i n v o l v e d i n e s t i m a t i n g t h e c o n s t r u c t i o n o f t h e P i n e T r e e Way d i v e r s i o n r o u t e i n 1970, w h i c h means he i s f a m i l i a r w i t h the g e o l o g y o f t h e a r e a , and t h e . t r a n s p o r t a t i o n o f c o n s t r u c t i o n m a t e r i a l s t o t h e a r e a , two i m p o r t a n t a s p e c t s i n e s t i m a t i n g c o s t s . U n i t c o s t s were o b t a i n e d f r o m H a f n e r , s u c h as c o s t o f curb and g u t t e r p e r l i n e a l f o o t and c o s t o f s i d e w a l k s p e r l i n e a l f o o t . An a d d i t i o n a l s o u r c e f o r u n i t c o s t was U n i t e d C o n t r a c t o r s , a n o t h e r Vancouver b a s e d c o n s t r u c t i o n f i r m w h i c h b u i l t 30,000 f e e t o f 6 f o o t wood f e n c i n g on t h e Upper L e v e l s Highway i n West Vancouver. The e s t i m a t e f o r 6 f o o t h i g h wood f e n c i n g w i t h c o n c r e t e f o o t i n g s c o m p l e t e l y i n s t a l l e d i s $20 a l i n e a l f o o t (1977 d o l l a r s ) compared t o H a f n e r ' s e s t i m a t e o f a s i m i l a r w a l l made of c o n c r e t e - $25 a l i n e a l f o o t . A p p e n d i x 3 g i v e s a f u l l breakdown o f c o s t s f o r each a r c h e t y p e . The c o s t s i n c l u d e : 1. New roadbed c o n s t r u c t i o n i n c l u d i n g g r u b b i n g , e x c a v a t i n g , two f e e t o f g r a n u l a r b a s e s and t h r e e i n c h e s o f a s p h a l t i c c o n c r e t e . 2. Curbs and g u t t e r s . 3. S i d e w a l k s . 4. B i n w a l l t y p e r e t a i n e d w a l l s . 5. 6 f o o t wood f e n c e s w i t h c o n c r e t e f o o t i n g s . 6. E x c a v a t i o n and d i s p o s a l o f m a t e r i a l ( f o r - d e p r e s s e d d e s i g n s 2 and 3 ) . 7. M a t e r i a l t r u c k e d i n t o s i t e ( f o r A r c h e t y p e 4 - berm). 8. E x c a v a t e and shape berms ( f o r c o m b i n a t i o n b e r m / e a r t h mound A r c h e t y p e s 5 and 6) . 9. Two f o o t h i g h s a f e t y w a l l s ( f o r A r c h e t y p e s 2, 3, and 6 ) . 10. C o n t i n g e n c y c o s t s - s t a n d a r d 15% ( i n c l u d e s r e l o c a t i o n o f u t i l i t i e s ) . 11. A d d i t i o n a l l a n d c o s t s (where, l a n d must be p u r c h a s e d i n e x c e s s o f t h e m u n i c i p a l owned r i g h t o f way o f 100 f e e t ) . A l l t h e u n i t c o s t s i n c l u d e l a b o u r , t r a n s p o r t a t i o n , e t c . , n e c e s s a r y i n c o m p l e t i n g t h e a s p e c t o f c o n s t r u c t i o n i n q u e s t i o n . U s u a l l y r e l o c a t i o n o f u t i l i t i e s i s a major expense. However, be c a u s e n o t a g r e a t d e a l o f d e v e l -opment p r e s e n t l y e x i s t s and c o n s i d e r a b l e e s t a b l i s h m e n t o f u t i l i t i e s w i l l o c c u r i n any e v e n t , a p a r t f r o m t h e p o s s i b l e c o n s t r u c t i o n o f b a r r i e r s , i t i s thought u t i l i t y c o s t s c o u l d be a d e q u a t e l y a b s o r b e d i n the s t a n d a r d c o n t i n g e n c y c o s t o f 15%. C o s t s o f o v e r p a s s e s a r e n o t i n c l u d e d because i t i s n o t known.-how many w o u l d be n e c e s s a r y and as d e s c r i b e d i n C h a p t e r 5 o v e r p a s s e s a l t h o u g h n o t r e q u i r e d i n a l l a r c h e t y p e s a r e recommended i n a l l . T h e r e f o r e c o n s i d e r i n g them w o u l d mean an e q u a l i n c r e m e n t i n c o s t and w o u l d n o t a f f e c t t h e c o m p a r a t i v e d i f f e r e n c e s i n c o s t s o f t h e f i v e a r c h e t y p e s . The p r e s e n t w i d t h o f r i g h t o f way f o r P i n e Tree Way i s 100 f e e t . I t w o u l d be i n a p p r o p r i a t e n o t t o i n c l u d e l a n d c o s t s i f e x t r a l a n d had t o be p u r c h a s e d , w h i c h i s t h e case i n A r c h e t y p e s 3, 4, 5, and 6. L a n d v a l u e s 69. were o b t a i n e d f r o m Penny and K e e n l e y s i d e A p p r a i s a l s L t d . , l a n d a p p r a i s e r s f o r The D i s t r i c t o f C o q u i t l a m . A l t h o u g h the l a n d f l a n k i n g P i n e t r e e Way i s p r e s e n t l y zoned a g r i c u l t u r a l and r e s i d e n t i a l , t h e v a l u e s a s s i g n e d t o t h i s l a n d must f o l l o w the p o t e n t i a l " h i g h e s t u s e " . T h i s r e l a t e s t o t h e o p p o r t u n i t y c o s t o f r e s o u r c e s o r i n p u t s ( i n c l u d i n g l a n d ) n e c e s s a r y i n " p r o d u c i n g " t h e f a c i l i t i e s when compared t o t h e i r most v a l u a b l e a l t e r n a t i v e u s e . The c o s t o f i n p u t s t o a f i r m a r e t h e i r v a l u e i n t h e i r most v a l u a b l e , a l t e r n a t i v e uses ... I t i s i m p o r t a n t t o n o t e t h a t the a l t e r n a t i v e c o s t o f an i n p u t may n o t e q u a l i t s h i s t o r i c a l c o s t , w h i c h i s d e f i n e d t o be t h e amount th e f i r m a c t u a l l y p a i d f o r i t . (1) The p r e s e n t " h i g h e s t use" w h i c h can be a p p l i e d i s c o m m e r c i a l , w h i c h commands $8 a s q u a r e f o o t , e s t i m a t e d by Penny and K e e n l e y s i d e . T h i s v a l u e i s a p p l i e d t o a l l l a n d a d j a c e n t t o P i n e t r e e Way. The v a l u e o f t h e e x i s t i n g r i g h t of way i s n o t c o n s i d e r e d i n t h e c o s t a n a l y s i s b e c a u s e each a r c h e t y p e must use t h e 100 f o o t s t r i p and t h e r e f o r e t h e c o m p a r a t i v e d i f f e r e n c e i n c o s t w o u l d no t be a f f e c t e d . I f t h e o b j e c t o f c o s t i n g was t o examine a l t e r n a t i v e uses o f i n p u t s ( s u c h as l a n d ) a s s i g n i n g t h e o p p o r t u n i t y c o s t o f a l l l a n d n e c e s s a r y , i n c l u d i n g t h e 100 f o o t r i g h t o f way, w o u l d be i m p e r a t i v e . B e f o r e d e a l i n g w i t h t h e c a l c u l a t e d c o s t s o f e ach a r c h e t y p e one p o i n t must be c l e a r l y e m p h a sized. T h i s i s t h a t a l t h o u g h i t appears c o n s t r u c t i o n c o s t i n g i s done i n a d e t a i l e d f a s h i o n , t h e c o s t s a r e n o t t o be c o n s i d e r e d e x t r e m e l y a c c u r a t e b u t o n l y " b a l l p a r k " f i g u r e s . T h i s i s because t h e u n i t c o s t s o b t a i n e d were average e s t i m a t e s w h i c h m i g h t have been s l i g h t l y d i f f e r e n t i f t h e n e c e s s a r y amount o f t i m e and d e t a i l e d c a l c u l a t i o n h a d been i n v e s t e d , as w o u l d be n e c e s s a r y i n a c o m p e t i t i v e b i d s i t u a t i o n . However, even i f t h e e s t i m a t e s doe n o t resemble a b s o l u t e c o s t s i t i s f e l t t h e y a r e r e a s o n a b l e a p p r o x i m a t i o n s and a f f o r d a good means o f comparing r e l a t i v e c o s t s o f t h e a r c h e t y p e s . O n l y t h e c r u c i a l c o m p a r a t i v e c o s t s w i l l 70. be d i s c u s s e d below. F o r a d e t a i l e d breakdown see A p p e n d i x 3. 6.2 COMPARATIVE COSTS OF THE CONTROL AND FIVE ARCHETYPES C o s t i n g t h e C o n t r o l s i t u a t i o n i s n e c e s s a r y t o e s t i m a t e a "base l i n e " c o s t . I f no b a r r i e r c o n f i g u r a t i o n i s c o n s t r u c t e d t h e e s t i m a t e d c o s t w o u l d o n l y i n v o l v e w i d e n i n g t h e p r e s e n t roadway f r o m two t o s i x l a n e s and t h e a d d i t i o n o f c u r b s , g u t t e r s and s i d e w a l k s . Two c o s t s a r e s u b m i t t e d (see A p p e n d i x 3 ) . The f i r s t assumes the p r e s e n t a s p h a l t s u r f a c e and roadbed a r e n o t i n c o r p o r a t e d i n t o r e c o n s t r u c t i o n - t o t a l c o s t o f $661,000 ( a l l c o s t s t o t h e n e a r e s t $1,000). I f t h e p r e s e n t roadbed and a s p h a l t s u r f a c e a r e i n c o r p o r a t e d t h e c o s t i s o n l y $391,000. The t o t a l w i d t h n e c e s s a r y f o r w i d e n i n g p l u s 20 f e e t f o r c u r b s , g u t t e r s and s i d e w a l k s i s 98 f e e t ; no e x t r a l a n d c o s t s a r e i n c u r r e d . A r c h e t y p e 2 i s by f a r t h e most e x p e n s i v e d e s i g n i n terms o f c o n s t r u c -t i o n c o s t s a l o n e . N o t b e i n g a b l e t o u t i l i z e any o f t h e p r e s e n t roadway -i t w o u l d be e x c a v a t e d - t h e t o t a l c o s t f o r A r c h e t y p e 2 i s $2,925,000. The most e x p e n s i v e ; i t e m w i t h i n the d e s i g n i s t h e b i n w a l l . ( B i n w a l l i s c o n s t r u c t e d o f l a r g e s t o n e s h e l d i n p l a c e by s t e e l u p r i g h t s and h o r i z o n t a l " p i n s " and i s c o n s i d e r a b l y l e s s e x p e n s i v e t h a n p o u r e d c o n c r e t e w a l l s . ) The c o s t f o r t h e n e c e s s a r y 126,720 s q u a r e f e e t o f t h i s b i n w a l l i s $1,267,000. I d e n t i c a l t o t h e C o n t r o l case t h e n e c e s s a r y r i g h t o f way w i d t h i s 98 f e e t ; t h e r e f o r e no e x t r a l a n d c o s t s a r e i n c u r r e d . A r c h e t y p e 3, i n r e s p e c t t o c o n s t r u c t i o n c o s t s d i f f e r s f r o m A r c h e t y p e 2 o n l y i n t h a t i t does n o t r e q u i r e t h e 12 f o o t h i g h r e t a i n e d w a l l . The t o t a l c o n s t r u c t i o n c o s t r e f l e c t s t h i s - $1,711,000. However, the t o t a l w i d t h o f r i g h t o f way n e c e s s a r y i s 134 f e e t . The e x t r a 34 f e e t i n w i d t h a t 8 d o l l a r s a s q u a r e f o o t c o s t s $1,436,000. The t o t a l c o s t i n c l u d i n g c o n s t r u c t i o n and l a n d i s t h e r e f o r e $3,147,000. A r c h e t y p e 4 i n c l u d e s i d e n t i c a l c o s t s t o t h a t o f t h e C o n t r o l e x c e p t i t 71. i s thought t h e e x i s t i n g r o a d b e d c o u l d n o t be i n c o r p o r a t e d i n t o the new d e s i g n b e c a u s e o f t h e " c h u r n i n g up" and d e t e r i o r a t i o n o f t h e p r e s e n t r o a d -b e d d u r i n g c o n s t r u c t i o n o f t h e new berms. The t o t a l c o n s t r u c t i o n c o s t i s $1,340,000, and t h e a d d i t i o n a l l a n d c o s t $2,957,000, r e s u l t i n g i n a t o t a l c o s t o f $4,29 7,000. A r c h e t y p e 5 i n c o r p o r a t e s a c o s t s a v i n g c o n s t r u c t i o n f e a t u r e . T h i s i s t h a t t h e c u t s e c t i o n i s d e s i g n e d t o be e q u a l t o t h e berm s t r u c t u r e i n terms o f c u b i c y a r d s o f f i l l . T h i s means t h a t t r a n s p o r t a t i o n c o s t s f o r t r u c k i n g m a t e r i a l o u t (as i n A r c h e t y p e s 2 and 3) o r t r u c k i n g m a t e r i a l i n (as i n A r c h e t y p e 4) a r e e l i m i n a t e d . The r e s u l t i s r e f l e c t e d i n a l o w e r c o n s t r u c -t i o n c o s t - $1,279,000. However, t h i s d e s i g n a g a i n e n t a i l s c o n s i d e r a b l e l a n d c o s t s - $2,957,000 - r e s u l t i n g i n a t o t a l c o s t o f $4,236,000. A r c h e t y p e 6 i s c o n s i d e r e d i d e n t i c a l i n terms o f c o n s t r u c t i o n and l a n d c o s t s t o A r c h e t y p e 5 e x c e p t t h a t t h e 2 f o o t s a f e t y w a l l i s n e c e s s a r y i n t h i s d e s i g n , r e s u l t i n g i n t h e s l i g h t l y h i g h e r c o n s t r u c t i o n c o s t o f $1,385,000 and t o t a l c o s t o f $4,342,000. T a b l e 14 compares t h e c o s t s o f t h e C o n t r o l and f i v e a r c h e t y p e s i n c l u d i n g b o t h c o n s t r u c t i o n and l a n d c o s t s . \ C o n s i d e r a t i o n o f w h i c h a r c h e t y p e i s most a p p r o p r i a t e i n r e s p e c t t o c o s t a l o n e depends on w h e t h e r e x t r a l a n d has t o be p u r c h a s e d f o r a d d i t i o n a l r i g h t o f way w i d t h . C o n s i d e r i n g c o n s t r u c t i o n c o s t s a l o n e A r c h e t y p e s 4, 5 and 6 a r e o f s i m i l a r " l o w " c o s t . A r c h e t y p e 2 i s t h e most e x p e n s i v e . However, i n c o r p o r a t i n g l a n d c o s t s c r e a t e s a new p i c t u r e . A r c h e t y p e 2 i s f a r l e s s e x p e n s i v e i n t o t a l c o s t t h a n 4, 5 and 6. T h i s d i s c u s s i o n w i l l be f u r t h e r p u r s u e d i n t h e c o n c l u d i n g c h a p t e r , when a l l v a r i a b l e s ( i . e . n o i s e , a e s t h e t i c s , c i r c u l a t i o n and c o s t ) a r e c o n s i d e r e d t o g e t h e r . 72. TABLE 14 CONSTRUCTION, LAND AND TOTAL COSTS FOR CONTROL AND FIVE ARCHETYPES (1977 DOLLARS TO NEAREST $1,000) (LAND COSTS CALCULATED AT $8 PER SQUARE FOOT) NAME CONSTRUCTION COSTS ADDITIONAL LAND COSTS TOTAL CONTROL (NOT USING EXISTING ROADBED) $ 661,000 none $ 661,000 CONTROL (USING EXISTING ROADBED) $ 391,000 none $ 391,000 ARCHETYPE 2 $2,925,000 none $2,925,000 ARCHETYPE 3 $1,711,000 $1,436,000 $3,147,000 ARCHETYPE 4 $1,340,000 $2,957,000 $4,297,000 ARCHETYPE 5 $1,279,000 $2,957,000 $4,236,000 ARCHETYPE 6 $1,385,000 $2,957,000 $4,342,000 6.3 ARE THE ARCHETYPES WORTH I T OR CAN THEY BE AFFORDED? The f i n a l q u e s t i o n n e c e s s a r y i n r e s p e c t t o c o s t i s , " I s i t w o r t h i t ? " . One s t u d y w h i c h a t t e m p t e d t o shed l i g h t on w h e t h e r n o i s e a t t e n u a t i o n was c o s t e f f e c t i v e was done i n C h i c a g o by R. Vaughan and L. H u c k i n s and e n t i t l e d , The Economics o f Expressway N o i s e P o l l u t i o n Abatement. (2) I n an e x t e n s i v e d a t a c o l l e c t i n g and c o m p u t e r i z e d a n a l y s i s n o i s e l e v e l s e m i t t e d f r o m freeway t r a f f i c were c o r r e l a t e d w i t h l a n d v a l u e s . I t was d e t e r m i n e d t h a t a d e c r e a s e i n p r i v a t e p r o p e r t y v a l u e s due t o n o i s e f r o m a d j a c e n t roadways j u s t i f i e d an e q u a l p u b l i c e x p e n d i t u r e t o reduc e n o i s e e m i s s i o n s t o a c c e p t a b l e l e v e l s . (3) ( I t c o u l d a l s o be w o r t h w h i l e f o r a d e v e l o p e r t o p r o v i d e e x t r a p r o t e c t i o n i f i t i n c r e a s e d t h e v a l u e o f t h e u n i t s t o t h e p u r c h a s e r . ) T h i s may be a r e a s o n a b l e d e d u c t i o n e x c e p t no a t t e n t i o n i s d i r e c t e d towards t h e p o s s i b l e r e d u c t i o n i n v a l u e o f p u b l i c p r o p e r t y w h i c h c o u l d r e s u l t f r o m h i g h e r n o i s e e m i s s i o n s . As t h e p r e s e n t case s t u d y i n v o l v e s t o a l a r g e degree p u b l i c space a p p l i c a t i o n o f t h e Vaughan and H u c k i n s f i g u r e s i s i n a p p r o p r i a t e . There a r e f u r t h e r r e a s o n s why t h i s " p r i v a t e p r o p e r t y d e v a l u a t i o n - b a r r i e r i n v e s t m e n t " c o r r e l a t i o n cannot be a p p l i e d t o t h e p r e s e n t case s t u d y . D a t a r e c o r d e d i n .the C h i c a g o s t u d y was c o l l e c t e d i n 1971 and 1972. (4) Land v a l u e s have no doubt f l u c t u a t e d somewhat so t h a t t h e C h i c a g o f i g u r e s c a n n o t be s p e c i f i c a l l y u s e d . The f u t u r e v a l u e o f p r o p e r t y a l o n g P i n e t r e e Way i s n o t c l e a r l y known; t h e r e f o r e i t i s i m p o s s i b l e t o make judgements about p r o p e r t y d e v a l u a t i o n due t o i n c r e a s e d n o i s e l e v e l s . I n a d d i t i o n t h e r e i s no g e n e r a l d a t a a v a i l a b l e , s i m i l a r t o t h e Chicago s t u d y d a t a , f o r t h e Vancouver r e g i o n , from w h i c h s p e c i f i c c o r r e l a t i o n s c o u l d be drawn t o t h e C o q u i t l a m c a s e . The r e s u l t o f t h e s e u n c e r t a i n t i e s s u r r o u n d i n g t h e " p r i v a t e p r o p e r t y d e v a l u a t i o n -b a r r i e r i n v e s t m e n t " c o r r e l a t i o n i s t h a t i t i s e x t r e m e l y d i f f i c u l t t o j u s t i f y t h e c o s t o f t h e a r c h e t y p e s i n a " c o s t e f f e c t i v e " c o n t e x t . To answer t h e q u e s t i o n , " I s i t w o r t h i t ? " , i n r e s p e c t t o c o s t remains a s i t u a t i o n where an a t t e m p t must be made t o p u t a q u a n t i t a t i v e v a l u e on a q u a l i t a t i v e improvement i n t h e e n v i r o n m e n t . The answer must come fr o m t h e c i t i z e n s and d e c i s i o n m a k e r s o f C o q u i t l a m . A s l i g h t l y d i f f e r e n t q u e s t i o n w h i c h can be t a c k l e d more e f f e c t i v e l y i s , "Can the m u n i c i p a l i t y a f f o r d t h e c o s t o f b u i l d i n g n o i s e b a r r i e r s ? " . P r e s e n t l y revenues a r e c o l l e c t e d t h r o u g h t h e S o i l Removal Bylaw by means o f a $.20 p e r c u b i c y a r d f e e f o r m a t e r i a l e x t r a c t e d . T h i s revenue i s n o t n eeded t o c o n t e n d w i t h t h e d e l e t e r i o u s e f f e c t s o f g r a v e l p i t o p e r a t i o n s as o p e r a t o r s a r e r e q u i r e d , t h r o u g h t h e i r own expense, t o r e h a b i l i t a t e and p r o v i d e t h e n e c e s s a r y equipment t o m a i n t a i n b o t h m u n i c i p a l and p r o v i n c i a l s t a n d a r d s . I f t h e s e funds were d i r e c t e d towards a l l e v i a t i n g t h e d e l e t e r i o u s s i d e e f f e c t s o f g r a v e l o p e r a t i o n s o u t s i d e t h e p i t a r e a s ( s u c h as h i g h t r a f f i c n o i s e ) , any one o f t h e a r c h e t y p e s c o u l d be a f f o r d e d . C o n s i d e r i n g the f o r e c a s t e d t r u c k volumes o f 3,000 t r i p s (two way) p e r w o r k i n g day (3,000,000 c u b i c y a r d s p e r y e a r ) , $6,000,000 c o u l d be g e n e r a t e d by t h e $.20 S o i l Removal Bylaw f e e i n f i v e y e a r s . 75. FOOTNOTES 1. E. M a n s f i e l d , M i c r o e c o n o m i c s , New Y o r k , W.W. N o r t o n and Company I n c . , 1975, pp. 162, 163. 2. R. Vaughan and L. H u c k i n s , The Economics o f Expressway N o i s e P o l l u t i o n  Abatement, Rand P a p e r S e r i e s , No. P-5475, 1975. 3. i b i d . , p. I X . 4. i b i d . , p. 63. CHAPTER 7: CONCLUSIONS AND RECOMMENDATIONS  7.1 THE CASE STUDY C o n s i d e r i n g n o i s e a t t e n u a t i o n r e s u l t s w i t h r e s p e c t t o the case s t u d y two a r c h e t y p e s emerge as b e i n g c o n s i d e r a b l y more e f f e c t i v e t h a n t h e o t h e r s i n t h e i r a b i l i t y t o c o n t e n d w i t h t h e t a r g e t s t a n d a r d f o r t h e p a r k a r e a o f 58 ± 2.5 dBA. (See T a b l e 15.) These are t h e berm d e s i g n ( A r c h e t y p e 4) and t h e c o m b i n a t i o n e a r t h s l o p e - b e r m d e s i g n ( A r c h e t y p e 6 ) . W i t h r e s p e c t to the 65 ± 2.5 dBA t a r g e t s t a n d a r d s e t f o r t h e c o m m e r c i a l , r e s i d e n t i a l , c i v i c and s c h o o l a r e a s , the berm d e s i g n emerges as s l i g h t l y more s u c c e s s f u l than the r e s t . ( I t i s w i t h i n 2.5 dBA o f 65 dBA a t p o i n t s ( 2 5 , 4 ) , ( 5 0 , 4 ) , ( 5 0 , 1 0 ) , (50,20) and (50 , 30) . See T a b l e 16 on t h e f o l l o w i n g page.) However, a l l the o t h e r d e s i g n s f a l l c l o s e l y b e h i n d i n t h e i r c a p a b i l i t y t o d e a l w i t h t h e 65 ± 2.5 dBA t a r g e t s t a n d a r d . I t appears t h e s u b s t a n t i a l b a r r i e r h e i g h t (18 and 21 f e e t ) i s t h e main r e a s o n f o r t h e s u c c e s s o f a l l the a r c h e t y p e s . However, as i s d e m o n s t r a t e d at p o i n t ( 5 0 , 4 0 ) , a l l the a r c h e t y p e s become l e s s e f f e c t a t e l e v a t i o n s o f 40 f e e t o r more (see T a b l e 16) . T a b l e 17 r e v e a l s the r e s u l t s o f t h e a e s t h e t i c e v a l u a t i o n . The berm d e s i g n ( A r c h e t y p e 4) and t h e c o m b i n a t i o n e a r t h s l o p e - b e r m d e s i g n ( A r c h e t y p e 6) emerge a g a i n as t h e most s u c c e s s f u l . The c i r c u l a t i o n e v a l u a t i o n f o u n d t h e r e was no o v e r w h e l m i n g l y d i s t i n c t i v e advantage i n any o f t h e a r c h e t y p e s a l t h o u g h " t h e y a l l p o s s e s s e d some p o s i t i v e and n e g a t i v e c i r c u l a t i o n f e a t u r e s . T a b l e 18 summarizes the r e s u l t s o f t h e c o s t e v a l u a t i o n . The v e r t i c a l r e t a i n e d w a l l d e s i g n ( A r c h e t y p e 2) e n t a i l s t h e h i g h e s t c o n s t r u c t i o n c o s t -$2,925,000. W h i l e the l o w e s t c o n s t r u c t i o n c o s t s a r e r e a l i z e d w i t h t h e berm and t h e two c o m b i n a t i o n e a r t h s l o p e - b e r m d e s i g n s t h e s e a r c h e t y p e s i n c u r t h e h i g h e s t l a n d c o s t s . However, t h e s e l a n d c o s t s , b a s e d on t h e $8/square 77. COMPARISON OF THE 5 ARCHETYPES IN RESPECT TO THE LAND USE TARGET STANDARDS Key f o r Tables * = "good" protection (within +2.5 of 65 dBA) / = "adequate" protection (within +5.0 of 65 dBA) x = "inadequate" protection (above +5.0 of 65 dBA). TABLE 15 COMPARISON OF ARCHETYPES WITH 58 ± 2.5 TARGET STANDARD ARCHETYPE DESCRIPTION RECEIVER COORDINATES (25,4) (50,4) (50,10) (50,20) (50,30) (50,40) 1. CONTROL (NO PROTECTION) > X X X No te: Coordinates (50,20), (50,30), (50,40) are not considered i n respect to the park target standard of 58 ± 2.5 dBA because heights from 20'- 40'above grade are not expected at roadside i n the park area. 2. VERTICAL/RETAINED X X X 3. EARTH SLOPE X X X 4. BERM •. / * / 5. COMBINATION EARTH SLOPE-BERM X • X X 6. COMBINATION EARTH SLOPE-BERM.(FULL PROTECTION * * * TABLE 16 COMPARISON OF ARCHETYPES WITH 65 ± 2.5 TARGET STANDARD ARCHETYPE DESCRIPTION RECEIVER COORDINATES (25,4) (50,4) (50,10) • (50,20) • (50,30) • (50,40) 1. CONTROL (NO PROTECTION) x X X X X X 2. VERTICAL/RETAINED X * * * * / 3. EARTH SLOPE X * * * X X 4,. BERM . *. * A * ft X 5. COMBINATION EARTH SLOPE-BERM X * * * * / 6. COMBINATION EARTH SLOPE-BERM (FULL PROTECTION) * * * * X X 78. T A B L E 17 v  A E S T H E T I C P R E F E R A B I L I T Y O F F I V E A R C H E T Y P E S A R C H E T Y P E ' D E S C R I P T I O N P R E F E R A B I L I T Y C O N T R O L 1 N O B A R R I E R S " L E A S T P R E F E R A B L E " A R C H E T Y P E 2 V E R T I C A L R E T A I N E D 1 | A R C H E T Y P E 5 C O M B I N A T I O N E A R T H S L O P E / B E R M i ! A R C H E T Y P E 3 E A R T H S L O P E 1 i A R C H E T Y P E 4 B E R M . i i A R C H E T Y P E 6 C O M B I N A T I O N E A R T H S L O P E / B E R M ( F U L L P R O T E C T I O N ) ' T Y " M O S T P R E F E R A B L E " T A B L E 18 . _ _ • . C O N S T R U C T I O N , L A N D A N D T O T A L C O S T S F O R C O N T R O L A N D F I V E A R C H E T Y P E S (1977 D O L L A R S T O N E A R E S T $1,000) ( L A N D C O S T S C A L C U L A T E D A T $8 P E R S Q U A R E F O O T ) N A M E C O N S T R U C T I O N C O S T S A D D I T I O N A L L A N D C O S T S T O T A L C O N T R O L ( N O T U S I N G E X I S T I N G R O A D B E D ) $ 661,000 none $ 661,000 C O N T R O L ( U S I N G E X I S T I N G R O A D B E D ) $ 391,000 none $ '391,000 A R C H E T Y P E 2 $2,925,000 none $2,925,000 A R C H E T Y P E 3 $1,711,000 $1,436,000 $3,147,000 A R C H E T Y P E 4' $1,340,000 $2,957,000 $4,297,000 A R C H E T Y P E 5 $1,279,000 $2,957,000 $4,236,000 A R C H E T Y P E 6 $1,385,000 $2,957,000 $4,342,000 f o o t " h i g h e s t use" c r i t e r i o n , a r e l i k e l y i n f l a t e d w i t h r e s p e c t t o t h e l a n d b o r d e r i n g t h e p a r k d e s i g n a t e d a r e a . The m u n i c i p a l i t y i s n e g o t i a t i n g f o r o w n ership o f t h i s l a n d (1) w h i c h p r e s e n t l y i s an unused b a r r e n expanse f o l l o w i n g e x t e n s i v e e x t r a c t i o n a c t i v i t y . T h e r e f o r e , d e s i g n s w h i c h a r e l a n d e x t e n s i v e ( A r c h e t y p e s 4, 5 and 6) may be a p p r o p r i a t e f o r t h e roadway a d j a c e n t t o t h e p a r k a r e a f r o m a c o s t p e r s p e c t i v e ( l o w e s t c o n s t r u c t i o n c o s t s w i t h r e d u c e d l a n d c o s t s ) . R e g a r d i n g t h i s c o s t f a c t o r and the s u p e r i -o r i t y o f A r c h e t y p e s 4 and 6 w i t h r e s p e c t t o n o i s e a t t e n u a t i o n and a e s t h e t i c s i t i s recommended A r c h e t y p e s 4 and 6 be c o n s i d e r e d a d j a c e n t t o t h e p a r k a r e a . The d e c i s i o n w h i c h must be made c o n c e r n i n g t h e r e m a i n i n g .35 m i l e s t r e t c h b i s e c t i n g t h e c o m m e r c i a l l y z o n e d a r e a i n v o l v e s a t r a d e - o f f between n o i s e a t t e n u a t i o n , a e s t h e t i c s and c o s t . W i t h l a n d c o s t s e s t i m a t e d a t $8/ s q u a r e f o o t , A r c h e t y p e 2 i s by f a r t h e " b e s t buy". The .35 m i l e l e n g t h w o u l d c o s t a p p r o x i m a t e l y $9 75,000 ( v e r s u s $1.4 m i l l i o n f o r t h e l a n d e x t e n s i v e d e s i g n s ) . However, w i t h r e s p e c t t o the n o i s e a t t e n u a t i o n and a e s t h e t i c c r i t e r i a A r c h e t y p e 2 i s s l i g h t l y i n f e r i o r (see T a b l e s 16 and 1 7 ) . The d e c i s i o n as t o w h e t h e r t h e m u n i c i p a l i t y s h o u l d s p e n d more money f o r one o f t h e more e f f e c t i v e b u t c o s t l i e r d e s i g n s must be l e f t t o t h e d e c i s i o n m a k e r s . As was s u g g e s t e d i n C h a p t e r 6, S e c t i o n 3, t h e m u n i c i p a l i t y a l r e a d y has a means o f r a i s i n g the n e c e s s a r y funds t h r o u g h the S o i l Removal Bylaw f e e s . I t i s f e l t t h e case s t u d y e v a l u a t i o n p r o v i d e s s u f f i c i e n t grounds f o r an i n f o r m e d d e c i s i o n by the D i s t r i c t o f C o q u i t l a m c o n c e r n i n g b a r r i e r c o n s t r u c t i o n t h r o u g h t h e p r o p o s e d Town C e n t r e development. The r e s u l t s o f t h i s s t u d y c o u l d a l s o c o n t r i b u t e t o t h e D i s t r i c t ' s r e e v a l u a t i o n o f o t h e r a l t e r n a t i v e s f o r a l l e v i a t i n g t h e p o t e n t i a l t r a f f i c n o i s e p r o b l e m . (These a l t e r n a t i v e s c o u l d i n v o l v e d e c r e a s i n g e x t r a c t i o n a c t i v i t y , t h e r e b y 80. d e c r e a s i n g n o i s y t r u c k t r a f f i c o r r e r o u t i n g t r u c k t r a f f i c . ) I n s p i t e o f t h e e f f e c t i v e n e s s o f t h e b a r r i e r s , they do r e p r e s e n t a c o n s i d e r a b l e a l t e r a -t i o n i n t h e r o a d s i d e e n v i r o n m e n t w h i c h may n o t be a c c e p t a b l e t o t h e d e c i s i o n m a k e r s . ( I t i s l i k e l y the p l a n n e r s d i d n o t t h i n k . 20 f o o t b a r r i e r s w o u l d be n e c e s s a r y when th e y recommended i n v e s t i g a t i n g " ... a d e s i g n s o l u t i o n f o r g r a v e l t r u c k s i n t h e p r o p o s e d c o r e a r e a , p o s s i b l y i n v o l v i n g grade s e p a r a t i o n " ( 2 ) . ) 7.2 GENERAL CONCLUSIONS AND RECOMMENDATIONS The methodology u s e d i n t h i s s t u d y p r o v e d t o be s u c c e s s f u l and i s recommended as a guide f o r t r a f f i c n o i s e b a r r i e r s e l e c t i o n and e v a l u a t i o n . The c r i t i c a l s t e p s o f t h i s method a r e : 1. F o r e c a s t volumes o f a u t o m o b i l e s and t r u c k t r a f f i c . 2. E s t a b l i s h t a r g e t n o i s e s t a n d a r d s . 3. S e l e c t an a p p r o p r i a t e n o i s e p r e d i c t i o n model (H a j e k ' s model i s recommended due t o i t s a c c u r a c y , d i v e r s i t y and ease o f a p p l i c a t i o n ) . 4. S e l e c t t h e o r e t i c a l l y s u b s t a n t i a t e d b a r r i e r d e s i g n s . '5. U s i n g t h e n o i s e p r e d i c t i o n model t e s t a t t e n u a t i o n e f f e c t i v e n e s s o f b a r r i e r s i n r e s p e c t t o t a r g e t s t a n d a r d s . 6. E v a l u a t e b a r r i e r s i n r e s p e c t t o : a. A e s t h e t i c s b. C i r c u l a t i o n c. C o s t . 7. Choose a p p r o p r i a t e b a r r i e r . O t h e r m a j o r f i n d i n g s o f t h i s s t u d y a r e : 1. F o r t h e volumes o f t r u c k s and c a r s used i n t h e case s t u d y a l l a r c h e t y p e s p r o v e d t o be a c o n s i d e r a b l e improvement o v e r t h e C o n t r o l s i t u a t i o n ( a r t e r i a l w i t h no b a r r i e r p r o t e c t i o n ) . 2. S u b s t a n t i a t i n g b a r r i e r a t t e n u a t i o n t h e o r y , the e f f e c t i v e h e i g h t o f a 81. b a r r i e r c o n t r i b u t e s s i g n i f i c a n t l y t o i t s e f f e c t i v e n e s s . 3. Comparing f u l l p r o t e c t i o n ( s i x l a n e ) t o p a r t i a l p r o t e c t i o n w i t h b a r r i e r s c l o s e t o the h i g h e s t n o i s e s o u r c e o f t r u c k s p r o v e d t h a t n e i t h e r d e s i g n i s o v e r w h e l m i n g l y more e f f e c t i v e t h a n t h e o t h e r . ( F u l l p r o t e c t i o n p r o v e d more e f f e c t i v e 25 f e e t f r o m t h e edge o f the roadway b u t a t 50 f e e t and at a l l e l e v a t i o n s the d i f f e r e n c e i n e f f e c t i v e n e s s o f t h e two t y p e s o f d e s i g n s i s m a r g i n a l . ) 4. D e s i g n s w i t h low c o n s t r u c t i o n c o s t s (berms and e a r t h s l o p e s ) p r o v e d t o be t h e most l a n d e x t e n s i v e and t h e r e f o r e c o u l d i n c u r e x t r a l a n d c o s t s . C o n v e r s e l y , t h e most e x p e n s i v e d e s i g n ( v e r t i c a l r e t a i n e d w a l l , A r c h e t y p e 2) uses the l e a s t r i g h t o f way w i d t h . The s e l e c t i o n o f a d e s i g n may i n v o l v e w e i g h i n g c o n s t r u c t i o n c o s t s a g a i n s e x t r a l a n d c o s t s . 5. The c u t and f i l l t y p e d e s i g n s o f A r c h e t y p e s 5 and 6 d i d n o t p r o v e t o be s i g n i f i c a n t l y c h eaper t h a n o t h e r d e s i g n s i n s p i t e o f t h e f a c t g r e a t volumes o f m a t e r i a l do n o t have t o be t r u c k e d i n o r o u t w i t h t h e s e d e s i g n s . E x c a v a t i n g c u t s and f o r m i n g berms i s n o t much cheaper t h a n t r u c k i n g i n m a t e r i a l f o r berms. 6. S u b s t a n t i a t i n g e x i s t i n g t h e o r y , the type o f t r a f f i c b a r r i e r s c o n s i d e r e d i n t h i s s t u d y a r e i n e f f e c t i v e above 40 f e e t from grade l e v e l a t d i s t a n c e s c l o s e t o t h e roadway ( w i t h i n 50 f e e t o f the edge o f t h e r o a d ) . A r c h i t e c t u r a l a c o u s t i c n o i s e c o n t r o l c o u l d be combined w i t h t r a f f i c n o i s e b a r r i e r s t o e n s u r e e f f e c t i v e a t t e n u a t i o n a t e l e v a t i o n s g r e a t e r t h a n 40 f e e t and d i s t a n c e s l e s s than 50 f e e t from t h e edge o f t h e r o a d . Minimum o f f s e t d i s t a n c e s c o u l d a l s o be imposed t o keep r e c e i v e r s w i t h i n b a r r i e r n o i s e shadows. A f u r t h e r s o l u t i o n c o u l d i n v o l v e i n v e s t i g a t i n g t h e p s y c h o l o g i c a l a s p e c t o f annoyance f r o m t r a f f i c n o i s e . I t i s w e l l documented t h a t annoy-ance f r o m t r a f f i c n o i s e i s n o t c o n s i s t e n t among i n d i v i d u a l s . (3) R e n t a l u n i t s w h i c h a r e e x p o s e d t o h i g h e r t h a n t a r g e t s t a n d a r d n o i s e l e v e l s c o u l d 82. have e n f o r c e d l o w e r r e n t s o r p o s t e d s i g n s w a r n i n g th o s e who m i g h t f i n d t h e l e v e l o f n o i s e a n n o y i n g . 7.3 RECOMMENDATIONS FOR FURTHER RESEARCH 1. One d e s i g n f e a t u r e n o t found i n t h e a v a i l a b l e l i t e r a t u r e e x c e p t f o r D. M a r s h a l l ' s s t u d y (4) i s a v e r t i c a l r e t a i n e d w a l l combined w i t h a h o r i -z o n t a l " o v e r h a n g " o v e r t h e t r a f f i c . H a j e k ' s method does n o t a c c o u n t f o r t h i s type o f d e s i g n and i t i s n o t known how the " o v e r h a n g " c o u l d be a p p l i e d t o t h e e f f e c t i v e h e i g h t e q u a t i o n . E m p i r i c a l r e s e a r c h , t e s t i n g t h e e f f e c t -i v e n e s s o f "overhangs", c o u l d p r o v e b e n e f i c i a l as t h i s f e a t u r e a p p ears u s e f u l i n o t h e r r e s p e c t s ( i . e . i t i s . n o t v i s u a l l y i n t r u s i v e and c o u l d save r i g h t o f way w i d t h f o r on-grade t r a f f i c l a n e s ) . 2. B a r r i e r e f f e c t i v e n e s s t e s t s c o u l d be made f o r e x i s t i n g man-made and n a t u r a l b a r r i e r s e m p l o y i n g t h e methodology s u g g e s t e d h e r e . Recommendations c o u l d r e s u l t r e g a r d i n g the e f f e c t i v e n e s s and p o s s i b l e a l t e r a t i o n o f e x i s t i n g b a r r i e r s . 3. I n c o n j u n c t i o n w i t h t h e above " t e s t s " n o i s e l e v e l s and b a r r i e r e f f e c t -i v e n e s s c o u l d be c o r r e l a t e d w i t h r e n t l e v e l s o r p r o p e r t y v a l u e s and w i t h a t t i t u d i n a l r e s p o n s e s t o t r a f f i c n o i s e . There appears t o be v e r y l i t t l e r e s e a r c h i n t h i s a r e a t o d a t e . FOOTNOTES 1. R e v e a l e d t h r o u g h d i s c u s s i o n s w i t h D i s t r i c t o f C o q u i t l a m p l a n n e r L. W o l f e . 2. D i s t r i c t o f C o q u i t l a m , The Community P l a n f o r t h e C o q u i t l a m C e n t r e  A r e a , P o l i c y R e p o r t No. 2/76, September 1976, p. 7. 3. W.J. Ga l l o w a y e t a l . o f B o l t , Beranek and Newman, Highway N o i s e :  Measurement, S i m u l a t i o n , and M i x e d R e a c t i o n s , NCHRP R e p o r t 78, 1969 84. BIBLIOGRAPHY J . J . H a j e k , " O n t a r i o Highway N o i s e P r e d i c t i o n Method", i n T r a n s p o r t a t i o n  R e s e a r c h C i r c u l a r , Number 175, J a n u a r y 1976. K. L y n c h , S i t e P l a n n i n g , M.I.T. P r e s s , 1962. J . J . H a j e k , O n t a r i o Highway P r e d i c t i o n Method, O n t a r i o , M i n i s t r y o f T r a n s p o r t a t i o n and Communications, 1975. D. M a r s h a l l , A M i n i m a l Community Impact Urban Freeway, t h e s i s f o r the S c h o o l o f Community and R e g i o n a l P l a n n i n g , U n i v e r s i t y o f B r i t i s h C o l u m b i a . E f f e c t s o f T r a f f i c and Roads on t h e En v i r o n m e n t i n Urban A r e a s , a r e p o r t p r e p a r e d by t h e O r g a n i z a t i o n f o r R e s e a r c h and Development, P a r i s , J u l y 1973. W.J. G a l l o w a y e t a l . o f B o l t , Beranek and Newman, Highway N o i s e : Measurement,  S i m u l a t i o n , and M i x e d R e a c t i o n s , NCHRP R e p o r t 78, 1969. C.G. Gordon e t a l . o f B o l t , Beranek and Newman, Highway N o i s e : A D e s i g n  Guide f o r Highway E n g i n e e r s , NCHRP R e p o r t 117, 1971. B a r r o n and S t r a c h a n , C o n s u l t i n g A c o u s t i c a l E n g i n e e r s , A Community N o i s e  S u r v e y , o f t h e G r e a t e r Vancouver R e g i o n a l D i s t r i c t , p r e p a r e d f o r t h e G.V.R.D., 1971. M. H a r m e l i n k and J . J . H a j e k , " N o i s e B a r r i e r E v a l u a t i o n and A l t e r n a t i v e s f o r Highway N o i s e C o n t r o l " , M.T.C. R e p o r t , No. RR180, 1972. G r e a t e r Vancouver R e g i o n a l D i s t r i c t , The L i v a b l e R e g i o n 1976-1986, 1975. R. Vaughan and L. H u c k i n s , The Economics o f Expressway N o i s e P o l l u t i o n  Abatement, Rand Paper S e r i e s , No. P-5475, 1975. 85. APPENDIX 1: ONTARIO HIGHWAY NOISE PREDICTION METHOD General The procedure for prediction of highway traffic noise using the Ontario method involves the use of the basic relationship between traffic flow density, traffic flow speed, distance and the resulting Li0> L j 0 and L s sound levels developed in this study, and the methodology developed by Gordon et al [2]. The following relationships between traffic flow volumes, traffic speed, distance and sound levels were established in this study: L s 0 = 30.4+ 14.5 log, o ( V c + 3 V t ) 11.5 log, o D + 0.16S L , 0 = 52.7+11.2 log, o ( V c + 3 V t ) - , 14.8 log, o D + 0.21 S L s = 56.5+11.1 log, o ( V c + V t ) 16.0 log, o D + 0.23 S where: L S 0 . L 1 0 ' L S = sound levels in dBA which were exceeded 50, 10 or 5 percent of the time V c - hourly volume of cars (GVW < 10,000 lb) V t = hourly volume of trucks (GVW > 10,000 lb) D = distance in feet from edge of pavement to the observer location S = average operating speed of traffic flow in miles per hour The above equations may be solved also by using the nomographs given in Figures B-1, B-2 and B-3 for L $ 0 ' L , 0 and L s sound levels, respectively. Both the above equations, and the nomographs calculate sound levels 4 feet (1.2 m) above ground assuming it is a simple case of continuous flow of traffic on an infinitely long, straight and level roadway with no intervening structures. Essentially, the nomograph for calculation of L 5 0 levels given in Figure B-1 replaces Figures 3, 4 and 5 of the Design Guide [2]. The nomograph for calculation of L 1 0 levels given in Figure B-2 replaces Figures 3, 4, 5 and 6 of the Design Guide. There is no provision in the Design Guide for calculation of L 5 levels. If the problem on hand involves more variables than those included in the nomographs (e.g., grade of highway or intervening structures), adjustments are made in a similar way as in the Design Guide. Variables Variables which are included in the Ontario Highway Noise Prediction Method are: ' i/ volume of cars; ii/ volume of trucks; iii/ traffic flow speed; iv/ distance; v/ intervening structures such as natural and artificial barriers, depressed and elevated highway sections, houses and vegetation; vi/ highway gradient; vii/ pavement surface texture; viii/ traffic flow characteristics; and ix/ ground attenuation effect. Procedure A/ Use of Nomographs Only If the first four variables listed above are reasonably constant on the length, of a roadway section of approximately 8D (where D is the distance from the roadway to the observer) and the last five variables are not applicabfe, the nomographs or equations can be used to provide sound levels. Examples of the use of nomographs are given in Figures B-1 to B-3. B/ Detailed Procedure The outlined procedure assumes that the reader is familiar with the procedure used in the Design Guide [2]. The steps involved are the following: 1. Determine the percentile of the desired sound level ( L s c L , 0 or L s ) . 2. Divide the highway into sections. They should be as long as possible but short enough to ensure that the following variables are approximately constant on the length of the sections; a/ car and truck flow; b/ t r a f f i c f low speed and traffic flow characteristics; c/ pavement surface type; d/ highway gradient; el break in the line of sight between the highway noise source and the observer's position. 3. Using the nomograph (or the equation), calculate the sound levels emitted by each element for a given location. Use perpendicular distance, D, as defined in Figure B-4. For each element, calculate the following adjustments to be applied to sound levels obtained in Step 3. 4.1 Adjustment for Element Size Figure B-4 is a schematic configuration of a h i ghway and an observer, and defines parameters used for element size adjustments. The element size adjustments of 1 to 14 dBA are subtracted from the predicted sound levels to account for the actual element size according to Figures B-5 and B-6 as reproduced from Reference [2]. The procedure is described in detail in Reference [8] and is based on the assumption that sound levels emitted by a roadway element at a given location are directly and linearly related to the angle subtended at the location by that roadway element. 4.2 Adjustment for Shielding Effect of Natural and Artificial Barriers (Including Depressed and Elevated Highway Sections) It is suggested that this adjustment be calculated according to the procedure described in Reference [5]. Briefly, the parameter H 2 H 2 rr + — is computed for each highway element and the appropriate adjustment is obtained from Table B-1 in Appendix B of this report T h e variables H, R and D are defined in Figure B-7 and may be obtained, for example, by plotting and evaluating highway cross sections. The height of the noise source above the pavement is determined using Table B-2. The height of the observer above ground should be at least 4 feet (1.2 m). The noise source maybe assumed to be located over the geometric mean of the distances f rom the observation point to . the nearest (df\j) traffic lane and from the observation point to the farthest (dF> traffic lane: d G = V d N • d F where: 6Q = geometric mean distance. 4.3 Adjustment for Highway Gradient Adjustment for highway gradient is made only for trucks on grades steeper than about 2 percent [2]. The total vertical climb from the bottom of grade negotiated by trucks should be at least 20 to 25 feet (6 to 7.5 m). Table B-3 gives coefficients which may be used to multiply truck volumes to account for the increase in truck noise on grades. The effect of these coefficients is similar to the effect of the gradient adjustment in Table 1 of Reference [2] . T h e coefficients are used in addition to the multiplication coefficient, 3, which is built into the models. For example, if the hourly truck volume in both directions is 100 on a long 5 percent grade, the number of trucks is multiplied by a coefficient of 2 and the resulting 200-truck volume is used for the calculation of sound levels by means of either the equations or the nomographs. 4.4 Adjustment for Pavement Surface Type Adjustment for pavement surface type should be based on Table B-4 of Reference [2] . 4.5 A d j u s t m e n t for Shielding Due to Vegetation According to Reference [2] , a design value of 5 d B A reduction for every 100-foot (30 m) depth may be. used if the trees are at least 15 feet (4.6 m) tall and sufficiently dense so that no visual path between observer and roadway exists. This attenuation should not exceed 10 dBA. 4.6 Adjustment for Shielding Effect of Houses Subtract 4.5 d B A for the first row of houses and 1.5 d B A for each additional row of houses to a maximum of 10 d B A [4]. 4.8 Adjustment for Ground Attenuation (see Section 4.2 E.) 5. For each element, arithmetically add all adjustments calculated in Step 4 to sound levels calculated in Step 3. 6. Logarithmically add sound levels of all elements. 7. Repeat steps 3 to 7 for other observation points. 8. The entire procedure can be repeated for different sound level percentiles. 4.7 Adjustment for Effect of Interrupted F low Calculation of sound levels at intersections should include traffic volumes and the corresponding average operating speeds on all intersection legs. It is recommended that L ! 0 and L 5 sound levels emitted by interrupted traffic flows containing at least 60 heavy trucks per hour be increased by about 2 or 3 dBA. L B -36.5+l l . l tefl|0(Vc*3Vt)-l6.0 log P O D *0.23S 70 GO 4 40 30-3 20 to 5 85 f-eo 3 0 -a o* LO UJ a. CO f-50 L 4 0 EXAMPLE-V e • 2000 vph V t • 200vph S «• SOmph D o 200ft L 0 • 69.5 dBA 25 n 30 . 40 50 60 -7 0 -80-100-140--eee-300-J 400 J 500 z UJ 2 u o a UJ 2 7 0 0 ^ s 1000 1400 2000 3000-1 5O00 J CO 5 Figure B-3, L 5 Sound Level Prediction ELEMENTS COMBINED OBSERVER £ we consider elements 2 and 3 as one element, the corresponding subtended angle, 0 2 . will be negative. Angle subtended for a semi-infinite element is negative only If the angle defined by the closest semi-finite element point, observer and the furthest semi-infinite point ( « ) is greater than 9 0 ° . Figure B-4, Definition Of Parameters For Element Size Adjustment -60 -40 -20 0 20 9 IN DEGREES 40 60 80 Figure B-5, Adjustment T o Account For Semi-Infinite Element Length Source: Reference [2] 20 40 60 80 100 9 IN DEGREES 120 140 160 Figure B-6, Adjustment T o Account For Finite Element Length Source: Reference [2] 89. Figure B-7, Barrier Configuration r 20,000 L B 0 »30.4t l4.5 lof l , 0 (V c +3V t } - l l .5 log | 0 D +0.16 S EXAMPLE-V c - 2000 vph V t ° 200 vph S • SOmph D • 200ft Lgj* 61.3 dBA 25 30 40 50 60 100 .140 -eee-i LU s I 300 400 500 700 1000 1400 2000 3000 5000 -J U l u z CO o 90. Figure B-1, L50 Sound Level Prediction F-5000 -4000 •3000 L | 0 -52.7*ll.2log | 0(V c +3V 1 )- l4.8 locj^D +0.21 S z TO-, BOA 40 30 20 to m — "O 1 2 I UJ O* UJ U l _| U l „ CO 80 70 60 50 40 EXAMPLE - V c • 2000 vph V, • 200 vph S • 50mph D • 200ft • 67.4 dBA 25-1 30-4 0 -50-6 0 -70 80 100 140 200 300 H 400 500 700-] 1000 1400 2000 3000 5000 J ui S UJ O 2 2 u. U l o z CO Figure B-2, L 1 0 Sound Level Prediction Table B-2, Apparent Height of Source (for use in Barrier Calculations) Table B-1, Barrier Attenuation Barrier Parameter H 2 + H 2 R D H Noise Level Adjustment (dBA) less than 0.05 Subtract 5 0.06-0.1 " 6 0 .12-0.2 " 7 0 .25-0.4 " 8 0.5 -0 .8 " 9 0.9 - 1 .2 " 10 1.3 - 1 , 9 " 12 2.0 -3.1 " 13 3.2 - 4 . 9 " 15 5 - 8 " 17 9 - 1 2 " 19 13 - 1 9 . " 21 20 - 2 9 " 23 over 30 " 24 S o u r c e : Reference (5J Percentage Trucks Apparent Height of (percent of total flow) Source (feet)* 1 or less 1 2 2 5 3 10 5 20 7 30 or greater 9 * / foot = 0.3048 m Source: Reference [5] Table B-3, Gradient Adjustment Gradient Coefficient For Truck % Vo lume Multiplication <2 1 3-4 1.5 5-6 2 >7 3 Table B-4, Classification of Road Surface as it Relates to Surface Influence on Vehicle Noise Adjust-Surface ment Type Description (dB) Smooth Very smooth, seal-coated. asphalt pavement - 5 Normal Moderately rough asphalt and concrete surface 0 Rough Roughasphalt pavement with large voids V, in. ( 12 .7 mm) or larger in diameter, grooved concrete +5 92. APPENDIX 2: DETAILED NOISE CALCULATIONS OF THE CONTROL AND FIVE ARCHETYPES dBA l e v e l s f o r t e s t c a s e r o a d c o n f i g u r a t i o n s ( w i t h and w i t h o u t b a r r i e r s ) a t L 1 Q l e v e l a t 25 f e e t and 50 f e e t f r o m r i g h t o f way edge ( a t 50 f o o t e l e v a t i o n s o f 4, 10, 20, 30 and 4 0 ) . *ALL FINAL CALCULATIONS ± 2 . 5 dBA. HORIZONTAL AND VERTICAL COORDINATES IN FEET (25,4) (50,4) (50,10) (50,20) (50,30) (50,40) CONTROL 1: 6-12' l a n e s on grade - no b a r r i e r e f f e c t 79.5 76.0 76.0 76.0 76.0 76.0 ARCHETYPE 2: 12' r e t a i n e d w a l l w i t h 6' f e n c e on t h r o u g h l a n e s - n o i s e l e v e l s f r o m element 1 w i t h o u t , b a r r i e r - a t t e n u a t i o n e f f e c t o f b a r r i e r - n o i s e l e v e l f rom element 1 w i t h b a r r i e r - n o i s e l e v e l s f r o m element 2 - combined e f f e c t . r- + 1.2 a d j u s t m e n t 73.5 17.0 56.5 70.0 71.6 72.8 71.0 17.0 54.0 65.0 65.4 66.6 71.0 15.0 56.0 65.0 65.5 66.7 71.0 13.0 58.0 65.0 65.8 67.0 71.0 10.0 61.0 65.0 66.3 67.5 71.0 8.0 63.0 65.0 67.2 68.4 ARCHETYPE 3: 12' e a r t h s l o p e w i t h 6' f e n c e - n o i s e l e v e l s f r o m element 1 w i t h o u t b a r r i e r - a t t e n u a t i o n e f f e c t o f b a r r i e r - n o i s e l e v e l s f r o m element 1 w i t h b a r r i e r - n o i s e l e v e l s f r o m element 2 - combined e f f e c t - + 1.2 a d j u s t m e n t 71.5 13.0 58.5 70.0 70.3 71.5 69.5 13.0 56.5 65.0 65.6 66.8 69.5 10.0 59.5 65.0 66.1 67.3 69.5 8.0 61.5 65.0 66.6 67.8 69.5 0 69.5 65.0 70.9 72.1 69.5 0 69.5 65.0 70.9 72.1 ( c o n t i n u e d ) 93. HORIZONTAL AND VERTICAL COORDINATES IN FEET (25,4) (50,4) (50,10) (50,20) (50,30) (50,40) ARCHETYPE 4: 12* e a r t h berm w i t h 6' f e n c e - n o i s e l e v e l s w i t h o u t b a r r i e r s 79.5 76.0 76.0 76.0 76.0 76.0 - a t t e n u a t i o n e f f e c t o f b a r r i e r 17.0 17.0 15.0 12.0 8.0 0 - n o i s e l e v e l s w i t h b a r r i e r 62.5 59.0 61.0 64.0 66.0 76.0 ARCHETYPE 5: combined 9' e a r t h berm w i t h 6' c u t and 6' f e n c e - n o i s e l e v e l s f r o m element 1 w i t h o u t b a r r i e r 70.5 68.5 68.5 68.5 68.5 68.5 - a t t e n u a t i o n e f f e c t o f b a r r i e r 17.0 17.0 15.0 12.0 9.0 6.0 - n o i s e l e v e l s f r o m element 1 w i t h b a r r i e r 53.5 51.5 53.5 56.5 59.5 62.5 - n o i s e l e v e l s f r o m element 2 70.0 65.0 65.0 : 65.0 65.0 65.0 - combined e f f e c t 70.0 65.2 65.3 65.6 66.1 67.0 - + 1.2 a d j u s t m e n t 71.2 66.4 66.5 66.8 67.3 68.2 ARCHETYPE 6: combined 9' berm w i t h 6' c u t and 6' w a l l - n o i s e l e v e l s f r o m element 1 w i t h o u t b a r r i e r 70.5 68.5 68.5 68.5 68.5 68.5 - a t t e n u a t i o n e f f e c t . of b a r r i e r 17.0 15.0 13.0 9.0 0 0 - n o i s e l e v e l s f rom element 1 w i t h b a r r i e r 53.5 53.5 53.5 59.5 68.5 68.5 - n o i s e l e v e l s f rom element 2 w i t h o u t b a r r i e r 65.0 63.0 63.0 63.0 63.0 63.0 - a t t e n u a t i o n e f f e c t o f b a r r i e r 19.0 19.0 17.0 15.0 12.0 9.0 - n o i s e l e v e l s f r o m element 2 w i t h b a r r i e r 46.0 44.o : 46.0 48.0 51.0 52.0 - n o i s e l e v e l s f r o m element 3 w i t h o u t b a r r i e r 60.0 58.0 j 58.0 58.0 58.0 58.0 ( c o n t i n u e d ) 94. HORIZONTAL AND VERTICAL COORDINATES IN FEET (25,4); (50,4) (50,10) (50,20) (50,30) (50,40) ARCHETYPE 6 ( c o n t ' d ) 1 • - a t t e n u a t i o n e f f e c t o f b a r r i e r 17.0 15.0 13.0 7.0 0 0 - n o i s e l e v e l s f r o m element 3 w i t h b a r r i e r 43.0 43.0 45.0 51.0 58.0 58.0 - combined e f f e c t 54.1 54.2 56.4 60.4 69.0 69.0 - + 2.5 a d j u s t m e n t 56.6 56.7 58.9 62.9 71.5 71.5 APPENDIX 3: DETAILED COST BREAKDOWN OF THE CONTROL AND FIVE ARCHETYPES ( A b b r e v i a t i o n s : s.y. = s q u a r e y a r d c y . =• c u b i c y a r d l i n . f t . = l i n e a r f o o t S.T.. = s u b t o t a l C.C. = c o n t i n g e n c y c o s t s A.C. = a s p h a l t i c c o n c r e t e E.L.C. = e x t r a l a n d c o s t s . ) ( C a l c u l a t i o n s t o n e a r e s t $1,000.) CONTROL 1 ( O l d r o a d bed i s n o t u t i l i z e d ) (a) New r o a d c o n s t r u c t i o n i n c l u d i n g c l e a r i n g , g r u b b i n g and e x c a v a t i n g : 2 f e e t o f g r a n u l a r b a s e s and 3 i n c h e s o f a s p h a l t i c c o n c r e t e a t $10/s.y. 78' x 5280' = 45,800 s.y. a t $10/s.y. $ 458,000 9'/s.y. (b) 10,560 f t . o f c u r b and g u t t e r a t $ 4 . 5 0 / l i n . f t . $ 48,000 (c) 10,560 f t . o f s i d e w a l k a t $ 6 . 5 0 / l i n . f t . $ 69,000 S.T. $ 575,000 15% C.C. $ 86,000 CONSTRUCTION TOTAL $ 661,000 No E.L.C. CONTROL 1 ( O l d r o a d bed u t i l i z e d ) . (a) 38' x 5280' = 22,300 s.y. a t $10/s.y. $ 223,000 9'/s.y. (b) 10,560 f t . o f cu r b and g u t t e r a t $ 4 . 5 0 / l i n . f t . $ 48,000 (c) 10,560 f t . o f s i d e w a l k a t $ 6 . 5 0 / l i n . f t . $ 69,000 S.T. $ 340,000 15% C.C. $ 51,000 CONSTRUCTION TOTAL $ 391,000 No E.L.C. 96. ARCHETYPE 2 - VERTICAL RETAINED WALLS (a) Roadbed and A.C. (same as C o n t r o l 1) $ 458,000 (b) E x c a v a t e and d i s p o s e o f m a t e r i a l 12' x 30' x 5280' = 70,400 c.y. a t $5.00/c.y. $ 352,000 27'/c.y. (c) Two 12' r e t a i n i n g w a l l s 2 x 12' x 5280' = 126,720 s q . f t . a t $10.00/sq. f t . ( b i n w a l l ) $1,267,000 (d) Two 6' f e n c e s a t $ 2 0 / f t 2 x 5280' x $20 $ 211,000 (e) 21,120 f t . c u r b and g u t t e r a t $ 4 . 5 0 / l i n . f t . $ 96,000 ( f ) 10,560 f t . s i d e w a l k a t $ 6 . 5 0 / l i n . f t . $ 69,000 (g) Two 2' " s a f e t y " w a l l s a t .05 c.y. c o n c r e t e l i n . f t . 5280' x .05 = 264 c.y. a t $175 c.y. x 2 $ 92,000 S.T. $2,545,000 15% C.C. $ 380,000 CONSTRUCTION TOTAL $2,925,000 No E.L.C. ARCHETYPE 3 - EARTH SLOPE WALL (a) Roadbed and A.C. (same as 1) $ 458,000 (b) E x c a v a t e and d i s p o s e 48' x 12' x 5280' = $5.00 c.y. $ 563,000 2 7 7 c . y . ( c ) Two 6' f e n c e s a t $ 2 0 / f t . 5280' x $20 x 2 * $ 211,000 (d) 21,120 f t . c u r b and g u t t e r s a t $ 4 . 5 0 / l i n . f t . $ 96,000 (e) 10,560 f t . s i d e w a l k a t $ 6 . 5 0 / l i n . f t . $ 69,000 ( f ) Two 2' " s a f e t y " w a l l s a t .05 c . y . / f t . 5280' x .05 = 264 c.y. a t $175 c.y. x 2 $ 92,000 S.T. 15% C.C. CONSTRUCTION TOTAL E.L.C, a t $8/sq. f t . 34' x 5280 TOTAL LAND & CONSTRUCTION ARCHETYPE 4 - BERM (a) T r u c k i n m a t e r i a l f o r two berms 432. 8.f... x 5280' = 84,500 c y . a t $4.50/c.y. 2 7 7 c . y . (b) Two 6' f e n c e s a t $ 2 0 / l i n . f t . $20 x 5280' (c) Roadbed and A/C (same as C o n t r o l 1) (d) 10,560 f t . c u r b and g u t t e r a t $ 4 . 5 0 / f t . (e) 10,560 f t . s i d e w a l k a t $ 6 . 5 0 / f t . S.T. . 15% C.C. CONSTRUCTION TOTAL , E.L.C. 5280' x 70' x $8/sq. f t . TOTAL LAND & CONSTRUCTION ARCHETYPE 5 - COMBINATION BERM-EARTH SLOPE (a) E x c a v a t e and shape berms a t $6.00/c.y. 6' x 39' x 5280' = 46,500 c y . x $6 2 7 ' / c y . (b) Two 6' f e n c e s a t $ 2 0 / l i n . f t . x 5280' x 2 (c) Road bed and A.C. (same as C o n t r o l 1) (d) 21,120 f t . c u r b and g u t t e r a t $ 4 . 5 0 / f t . (e) 10,560 f t . s i d e w a l k a t $6.50/ft. $1,489,000 $ 222,000 $1,711,000 $1,436,000  $3,147,000 $ 380,000 $ 211,000 $ 458,000 $ 48,000 $ 69,000 $1,166,000 $ 174,000 $1,340,000 $2,957,000  $4,297,000 $ 279,000 $ 211,000 $ 458,000 $ 96,000 $ 69,000 S.T. $1,113,000 15% C.C. $ 166,000 CONSTRUCTION TOTAL $1,279,000 E.L.C. 70' x 5280' x $8/sq. f t . $2,957,000 TOTAL LAND & CONSTRUCTION $4,236,000 ARCHETYPE 6 - COMBINATION BERM-EARTH SLOPE, FULL PROTECTION (a) Same c o n s t r u c t i o n c o s t s as 5 (S.T.) $1,113,000 (b) P l u s two 2' c o n c r e t e " s a f e t y " w a l l s $ 92,000 S.T. $1,205,000 ' 15% C.C. $ 180,000 CONSTRUCTION TOTAL $1,385,000 E.L.C. 5280' x 70' x $8/sq. f t . $2,957,000 TOTAL LAND &.[CONSTRUCTION $4,342,000 

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