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UBC Theses and Dissertations

A minimal community impact urban freeway Marshall, David Stanley 1976

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A MINIMAL COMMUNITY IMPACT URBAN FREEWAY by DAVID STANLEY MARSHALL B.A., University of British Columbia, 1972 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS in THE FACULTY OF GRADUATE STUDIES School of Community and Regional Planning We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA August, 1976 © David Stanley Marshall, 1976 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of Community and Regional Planning The University of British Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date August 25, 1976 - i i -ABSTRACT From several points of view, freeways are a desirable urban technology. Not only do they provide high levels of mobility and traffic capacity, but their safety, fuel consumption and pollution-generation characteristics are the best available. Even in terms of noise generation and i t s impact on the urban environment, i t i s desirable to have maximum traffic diversion from surface streets to appropriately designed freeway facilities. Yet freeway development i s not without i t s costs. Opposition has grown, and now assumes a dominant position, politically, throughout much of North America, because the construction of freeways has often entailed severe disruptions of settled communities. These disruptions are referred to collectively as "community impact". The problem of this paper i s the design and performance evaluation of a limited form of freeway, a form which attempts to minimize community impact. To the extent that such a form i s possible, the environmental and other advantages of continuous-flow operation of motor vehicles will be available at lower social cost. The study begins by identifying the impacts to be avoided. "Res-idential displacement", "visual intrusion", JL'noise impact" and "traffic focal points and 'dumping' of traffic" are potential impacts of freeway construction and operation. Because of the nature of the designs being considered, "difficulties of local access and parking" i s included for examination, as i s the satisfactoriness of the highway driving environ-ment. - i i i -The general conclusions of the study are as follows. (1) Residential displacement would be limited to the removal of one house on the 3»2 mile test route. (2) The highway would not be visually intrusive since i t would be completely hidden from view. (3) At maximum noise generation, one of the test designs would produce no impact at nearby buildings and from "marginal" to "definite" impact at sidewalks adjacent to the facility; the other design would produce a "marginal" impact at the building facade and a "definite" impact at the sidewalk, (k) There would be no dumping of traffic in the study area. (The facility performs only the line-haul function with no collector/distributor element.) (5) Local access and parking could be assured, but would require the upgrading of rear lanes the parking of vehicles on private property. (6) The visual quality of the highway driving environment, though less than ideal, is judged to be satisfactory. Unfortunately the less effective of the designs from a noise containment point of view i s probably the most desirable aesthetic-ally. (7) Total development cost of each of the "minimal impact" designs approximates the total dollar costs of conventional inner-city freeways. It is concluded that minimal impact freeways appear to be feasible, both technically and economically, for the line-haul function across inner suburbs. Since i t now appears possible to construct limited forms of freeway with l i t t l e adverse community effect, freeways should no longer be considered a non-option for builteuppareas. -iv-INTRODUCTION p. 2 CHAPTER 1: THE STUDY'S SCOPE & METHOD ....p.8 1.1 Limits of the Study Area; Types of Impact to be Examined 1.2 Procedure to be Followed CHAPTER 2: FACILITY DESIGN & DEMONSTRATION p.11 2.1 Design Strategy 2.2 Cross-Sectional Design: six examples 2.3 Application to an Existing Urban Situation 2.4 Traffic Diversion to "Test Facility" CHAPTER 3: PERFORMANCE EVALUATION p.28 3.1 Community Impact Analysis: a l l factors except noise 3.1.1 residential displacement 3.1.2 visual intrusion 3.1.3 traffic focal points and dumping 3.1.4 local access and parking 3.1.5 loss of street trees 3.2 The Environment for Driving 3.3 Noise Impact Analysis* p.46 3.3.1 development of a criterion of impact 3.3.2 defining degrees of noise impact 3.3.3 noise simulation -method -some difficulties in application -shielding effect of test designs -combined exposure from two sources 3.4 Financial Cost CHAPTER 4: SUMMARY Se CONCLUSION p.82 4.1 Summary of Study and Findings 4.2 Conclusion 4.3 Policy Implication LITERATURE CITED P«90 APPENDIX I: Method for Deriving Construction Cost Estimates p.92 APPENDIX II: Calculation of Theoretical Noise Exposure p.95 APPENDIX III: The Study Area in Detail p.97 -V-List of Tables Table I Comparison of Design Features, Six Cross-Sectional Designs p.18 Table II P.M. Peak Hour CBD Person Trips, 1985 p.26 Table III Noise: Recommended Maximum Daytime Levels, Various Jurisdictions and Sources.. p.49 Table IV Gross Highway Noise p.59 Table V Vertically Retained Design: Calculated L-10 Highway Noise Exposure at Sidewalk and Building Facade p.69 Table VI Earth Slope Design: Calculated L-10 Highway Noise Exposure at Sidewalk and Building Facade «p*70 Table VII Vertical Cut: Combined L-10 Exposure at Sidewalk with Both Portions of Facility Operating Simul-taneously; Various Conditions of Speed & Flow... p.71 Table VIII Construction Cost Estimates, Five Forms of Freeway Construction (millions of 1971 dollars) p.79 Table IX Total Development Cost of a Freeway in the Prior-Venables Corridor,'Various Arrangements and Types (millions of 1971 dollars) p.81 List of Figures and Illustrations Figure 1 Cross-Sectional Design: Six Examples p.13 Figure 2 Noise Shielding p.19 Figure 3 Section Through Study Area p.22 Figure 4 The Inner Suburbs of Strathcona, Grandview-Woodland and Hastings-Sunrise.. p.23 Figure 5 'Corridor B', Location of Test Facility p.24 Figure 6 Maximum Discontinuity in Route Alignment, 132 ft p«30 Figure 7 Connector Alignment for Discontinuous Segments of Route: 40 mph design speed p.32 - v i -List of Figures (cont'd) Figure 8 Local Access and Parking: Earth Slope Design p«38 Figure 9 Access Via Rear Lanes p.4l Figure 10 Focal Length and Angle of Vision at 45 mph p.43 Figure 11 Relative Intensities of Various Common Sounds p.4? Figure 12 Degrees of Noise Impact, Defined p.53 Figure 13 Gross Estimate of Highway Noise Exposure p.58 Figure 14 Noise Reduction Provided by Various Highway Configurations p.62 Figure 15 Area Free of Direct Exposure to Noise p.64 Figure 16 Calculating 'Effective Depth' of Depression p.66 Figure 17 Combined Exposure at Sidewalk from Two Sources (located one block apart) Operating at Maximum Noise Generation P«73 Figure 18 Relative Construction Cost of Urban Freeways p.77 2 {Excerpt} "Report On Transportation For A Livable Region" (Citizens Policy Committee for Transportation and Trans-mission): submitted to the Board of the Greater Vancouver Regional District, October 1973s SUBJECT: FREEWAYS IN THE URBAN AREA SITUATION: There are presently two freeways, Burnaby and Deas Freeways, in the GVRD and none in the City of Vancouver, putting this area in a unique position compared to most every other city in North America. . . . POT TPY FURTHER CONSTRUCTION OF FREEWAYS IN THE GVRD STATEMENT: MUST BE BANNED AT ALL COST. Antipathy to urban freeways has grown to such an extent that outright and automatic opposition—to a l l new construction—is the strongly prevailing tendency. The dominance of this position is not difficult to understand since the image of "freeway as despoiler" is grounded in experience only recently past; and when important values are threatened (particularly when a situation seems out of control) the natural tendency i s to 'shut the whole thing down*. In the case of freeway and other urban road construction^just such a reaction has set in. It is a panic reaction, appropriate in emergencies. But for the development of public policy in the longer term, such convenient dichotomies as are associated with the above view ("freeway versus city", "traffic vs. environment", "environment for living vs. environment for making a living")—having served their purpose—should, like spent cartridges, be similarly abandoned. 3. Unless the incompatibility of traffic and environment i s accepted as less than absolute, matters may very well become worse for both. To be specific: in growing regions with growing traffic, attempts to "hold the line" on the automobile and its consequences by restriction  of investment in traffic facilities will likely have these effects: 1) no new facilities materialize 2) traffic service declines 3) environmental quality worsens, ae traffic, having nowhere else to go, f i l l s city streets. Having a high proportion of vehicular traffic in the streets (rather than on grade separated facilities) appears to be an undeniable o consequence of denying new capacity to growing traffic. Although new urban road construction i s invariably opposed on environmental grounds, traffic in the streets is 'very bad news' environmentally; particularly, in terms of safety, fuel economy, air pollution generation, and noise impact: safety: Direct two-way street intersections have 32 elementary conflicting manoeuvres. Approximately 1/3 of a l l road traffic accidents occur at intersections in urban areas and approximately 1/2 of a l l road 2 traffic accidents in urban areas occur at street intersections. fuel economy: 'Stop and go city traffic* requires greater energy expenditure per mile travelled than vehicles in continuous flow operation (because more energy i s required to repeatedly overcome inertia than to maintain a constant cruise condition). Aside from a somewhat accelerated decline in petroleum stocks, this is of concern because of impacts on the natural environment of new or accelerated petroleum development. air pollution generation: For gasoline-engined vehicles, concentration of pollutants in the exhaust is generally lowest in cruise conditions, and highest in acceleration, deceleration and idling. (See figure, overleaf). In other words pollution generation varies as the operating Kevin Lynch, Site Planning. MIT Press 1962, p.184. 2 Research into Road Safety at Junctions in Urban Areas; a report prepared by an OECD Road Research Group, October 1971; Organisation for Economic Co-operation and Development, Paris, p.41. 5. ^1 4} 57 •9f SI fl in Vi n •5" IZ 6 3 0 o o [ j p t M&J {Aatt} [caving jptfetj !0 1 ro t o o "OPERATING CONDITIONS AND POLLUTANT GENERATION: GASOLINE ENGINE VEHICLES" '('source: Sherwood P.T. & P.H. Bowers. Air Pollution from Road Traffic - a -rgjri:ew_gf_the__pjg8ent^ Research Laboratory Report LR 352, WITK06EN/ OXIDES 6. conditions, and the worst operating conditions from an air-quality point of view are those of stop and go city street traffic. noise impact; "Siiice stop-and-go traffic provides the highest noise levels, traffic management schemes which smoothen the flow of vehicles . . . also reduce noise levels.""^ Beranek gives the noise of a "street" as 80 dBA (see Fig .11, p.47) while Lynch l i s t s a "busy street" as 70-80 decibels. The impact of such traffic noise on the urban public environ-ment i s especially severe^ since the very streets which function as major traffic carriers to a large extent constitute the urban public environ-ment . synopsis & conclusion Antipathy to urban freeways has grown to the extent that virtually a l l new construction i s blocked. Unfortunately, such citizen intervention seems most likely to produce the unintended consequence of a degraded urban public environment, as traffic i s forced to use the streets. Is i t possible to obtain the environmental advantages of freeway (i.e. "continuous flow") operation of motor vehicles, as well as some of the transportation benefits, while avoiding most of a l l of the adverse community impacts normally associated with freeway construction and operation? Effects of Traffic and Roads on the Environment in Urban Areas; a report prepared by an OECD research group, July 1973. Organisation foreEconomic Co-operation and Development, Paris 4 Kevin Lynch, Site Planning, MIT Press 1962, p.99 7. More strongly stated: "Is a completely null impact urban freeway possible?" (i.e. a freeway which avoids a l l serious deleterious effects on the immediate environment through which i t passes). "If such a facility is possible, can i t be applied to achieve positive environmental impact?" The second of these questions is formally beyond the scope of the present limited study; yet i t is important to state since i t provides a framework and a perspective for the current work: i f i t were possible to design high capacity traffic carriers which did not themselves create adverse community impacts, then i t would presumably be possible to insert such facilities in heavily-trafficked corridors to achieve positive environmental impact— as traffic and its negative effects were diverted from surface streets to the "null impacting" facility. CHAPTER 1 THE STUDY'S SCOPE AND METHOD The major difficulty for environmental traffic control by the method just outlined, consists in the design of high capacity traffic 1 carriers which do not themselves impose adverse community impacts. Such facilities will be called "null impact urban arterials". The term "null impact": indicating the absence of serious deleterious 2 effects; and applying to the highway's immediate environment. 1.1 limits of the study area; types of impact to be examined It should be strictly noted that the term "null impact" as used in the remainder of this document refers to a specific study area: "the immediate environment through which the facility passes": and excludes areas and effects beyond the terminals, and beyond strictly speaking, i t is not necessary that the facility to which diversion is to be made be absolutely "null impact" in order that an overall positive result should occur. However, i t i s desirable—if only because a solution which makes some people better off while making no-one worse off i s to be preferred, in general, to one which yields a net improvement while transferring some of the costs. Furthermore, by attempting to design facilities completely free of negative effects, the designs actually produced (which inevitably will f a l l short of the ideal) will likely be superior to the results of an exercise with a more modest objective. Finally, such a design is sought because the more completely "null impact" a diversion facility i s , the more certain we can be (without additional evidence) that, in terms of benefits, i t would be "net producing" i f inserted in heavily trafficked situations. 2 the term's restricted application is justified on two grounds: (i) the "immediate environment" is the area in which adverse impacts can reasonably be expected to be most severe; (ii) in the wider area, the highway's impact should be bothv.substantial and positive (rather than "null" and "negative"). 9. adjacent properties along the length of the route. For this reason, and because the types of impact to be examined form a subset of a l l possible types , the term will appear in single quotation marks. To qualify as 'null impact1, a facility must substantially avoid the following problems: 1) residential displacement: the destruction of housing and forced relocation of residents 2) visual intrusion: due to highway structures which: (a) are unsightly in themselves, (b) block significant views, or (c) cause loss of privacy by affording views into adjacent residential property 3) noise impact: disruptive levels of highway noise; (see Chapter 3 for the development of a criterion of noise impact) k) traffic focal points and traffic 'dumping': 'dumping': large quantities^ of traffic exiting from freeways to grade streets; "focal points": points of focal attraction for traffic seeking highway access 5) difficulties of local access and parking 6) visually poor highway driving environment '"adjacent" means "fronting" properties, except that for simplicity the study boundary i s extended to mid-block on both sides of each portion of the facility, regardless of the fronting on non-fronting status of the included property. 2 although the l i s t i s not exhaustive, i t is felt that a l l impact types of more than minor importance have been included. (This is not to say, however, that a l l those included are of equal importance.) because of i t s continuous flow condition, the ability of a freeway lane to carry traffic i s more than double that of an ordinary street lane (perhaps 2000 vehicles per hour vs. 800-900). A freeway's ability to assemble traffic from a wide contributing area, to concentrate i t in space and time, and then to supply i t in large 'doses' to localized receiving areas i s what i s meant by "dumping". 10. 1.2 procedure to be followed The study's purpose, narrowly defined, is to determine the effectiveness and cost of certain designs in achieving the performance criteria of 'null inpact' arterials. To achieve this purpose the following procedure will be used: (1) a "design strategy" will be outlined and i t s physical expression defined. (That is to say, a proposed method of meeting the criteria will be stated and sample designs produced) (2) two of the sample designs will be selected for application to an existing urban situation (to obtain a basis for performance evaluation) (3) evaluations will be made (as precisely as the nature of the case permits) for each of the impact types previously identified (4) comparative cost estimates will be developed ( 5 ) conclusions will be drawn regarding the success or failure of the selected designs CHAPTER 2 FACILITY DESIGN AND DEMONSTRATION 2.1 design strategy The approach i s essentially a simple one consisting of four elements: -locate the highway within existing street right-of-way in two separate open cuts -exclude heavy trucks from using the facility -keep operating speeds to moderate levels -construct the highway without interchanges along the length of i ts route The first element i s intended to secure needed right-of-way while avoiding residential displacement. Since, in the case of local streets, right-of-way widths are typically as l i t t l e as 66 feet, advantage must be taken of the fact that there is no compelling technical reason to combine both directions of travel on a divided highway in exactly the same location. By divorcing the directions of travel and using two existing street rights-of-way, new high-capacity traffic facilities can be accommodated without residential 1 displacement. The highway's below-grade location i s intended to reduce noise impact and eliminate the possibility of visual intrusion. Vehicle as long as the streets being employed for the purpose are themselves continuous type and operating speed restrictions are related to noise impact alone. Large trucks (particularly those with diesel engines) produce substantially greater noise output than average motor vehicles. Since speed, too, i s related to highway noise generation, i t was chosen as an additional point of intervention. Elimination of interchanges is designed to eliminate the problem 2 of 'dumping* along the route length. This has the effect of turning the facility into a bypass freeway. It will be applied to the line-haul problem across inner suburbs: on the assumption that, i f such a facility has any serious application, this will be one of them. 2.2 cross-sectional design: six examples Appearing in Fig.1, "A" to "F", are six cross-sectional designs of facilities narrow enough to be accommodated within 66 foot right-of-way. (To be precise, two of the designs ("C" and "F") require narrow strips of additional land to be taken from the yards of fronting properties; 3 and 5 feet, respectively.) Three of the designs employ "vertically-retained" construction; and the remaining three, the more economical "earth slope" form. Each will be discussed in turn. 'Highway Noise: Measurement, Simulation, and Mixed Reactions, Galloway, Clark and Kerrick of Bolt, Beranek and Newman Inc., [US] National Cooperative Highway Research Program Report 78, Highway Research Board, 1969» 2 no egress = no 'dumping'; no access = no focal traffic points FIG.1: Cross-Sectional Design: six examples • a "vertical" or "retained" open cut • the continuous concrete 'box' which houses the roadway occupies 33 feet of lateral dimension; this allows two 11 foot local streets and two 31k foot sidewalks to be accommodated as well • there is room for neither the tradit-ional planting strip nor for parking on the local access streets • travelling lanes in the cut are a f u l l 12 feet wide. The left wall is 3 feet from the left edge of the travelled way; the right wall, 8)4 feet from the right lane-edge. The cantilevered section i s set back 3 feet from the right edge of the right lane; its overhang is Ik feet above finished grade. »over the mouth of the cut are s i t -uated vine-laden hoops of indeter-minated spacing. Their function i s two-fold: (1) to bring greenery into an otherwise totally "concrete" driving environment; (2) to soften the effect of introducing concrete in the residential environment. At i t s highest point the canopy i s 25 feet above the finished grade of the travelled way. • a stabilized earth-slope open cut; angle of slope: k5° • width of travelling lanes: 11)4 feet « emergency stopping lane: 7J& feet (plus % foot overhang) . • sidewalks are 3 feet wide, with 2 foot separator strips to k foot high walls • disadvantages: i . no room for local access streets, parallel and adjacent to facility i i . no street parking i i i . less effective noise shielding than vertical cut • advantages: i . greater degree of openness of driving environment (a factor somewhat offset by greater need for cross-overs to maintain ease of property access) i i . a less costly form than vertically retained construction • "retained" open cut, cantilevered both sides •design allows for: (i) two 12 foot arterial travelling lanes; (ii) two 6 foot emergency stopping lanes,(each with % foot overhang to wall); ( i i i ) two 18 foot local one-way streets, for access and parking • since the sidewalks must be placed on private property, 3 feet of land-taking is required on each side . "D" resembles "B" in a l l important respects except that i t i s furnished with large-scale plant material. This i s achieved by period-ically indenting the sloped cut to erect a vertical retaining wall; and by the use of planters. (Note that the usual convention indicates depth: objects in the foreground appear in solid line while those in the background are dashed.) •a simple, vertically retained, cutting, with a wide (37 foot) overhead opening •travelling lanes: 11$ feet stopping lanes: 6$ (+J6) feet local streets: 10 (+#) feet •no street parking; 3 foot sidewalks •resembles "B" and "D" in most respects; however, elimination of the emergency stopping lane, and incorporation of 5 feet of land on each side of the r/o/w, together permit inclusion of two local streets. These are 10 feet wide with % foot overhang. • no street parking i s possible • main advantages: i . more effective noise shielding at the sidewalk than "B" or "D" i i . lower cost construction than "vertically retained" form, yet permits local access at the property front. TABLE 1: COMPARISON OF DESIGN FEATURES, SIX CROSS-SECTIONAL DESIGNS item A 8 c D e F comments community environment (1) local access street at property front? yes no yes no yes yes community environment (2) street parking? no no yes no no no community environment (3) noise shielding at sidewalk 7' 22' 8' 13* see note below driving environment (k) emergency stopping lanes in cut? yes yes YES yes YES no yes = one side YES m both sides driving environment (5) "openness" of cut (i.e. width of overhead opening) 30' 5V 27' 37' k7 • driving environment (6) vegetation in cut? yes yes no yes (extensive) no yes driving environment note: Blocking the line-of-sight between source and receiver i s essential to noise shielding. While a l l of the designs achieve blockage, some shield more effectively than others. This is because the zone which i s free of direct exposure (the "sound shadow") varies in height. Extent of the various sound shadows i s shown in (3) above; method of calculation is shown opposite (Fig.2). 20 As should be evident from the preceding discussion, each design has i t s points of strength and weakness. Each one attempts to optimize, within a narrow physical space, a variety of conflicting requirements. Table 1 shows that the range of solutions developed, affects—differentially— each* of two distinct, environments: "community" and "driving". Attempts to achieve more completely the requirements of either, tend to diminish 1 or even preclude the achievement of certain items in the other. In a conflict such as this, the interests of only one side can be maximized. From an overall point of view, which of these approximate solutions i s best? The answer will depend on the situation into which the design is to be inserted; but even more, on the relative weighting of the values 2 subject to trade-off in the design process itself. For purposes of application and evaluation, designs "A" and "B" will be used. (Reference may, however, be made to other of the designs for example, noise barrier placement: the closer to the edge of the travelled way the barrier i s situated, the more effective—but also, the more constricted the visual environment of the driver in the cut. 2 assuming equal importance for each—and on the basis of only those items listed in Table 1—design "C" ranks highest; "E" and "A" second; "D" and "F" close thirds; and "B" i s the straggler of the pack. A slightly different method of scoring (in which "streets" and "street parking" are combined to form a single category) yields a more closely bunched result; the order, however, i s unchanged, with the exception of "D" which jumps from fourth to second place. (As the text indicates and this note will serve to emphasize, design rank-order depends largely on the rank order of the design features sought.) as the paper progresses.) This selection should be considered arbitrary rather than preferential. Fig.3 (next page) illustrates the designs in context: i.e. when inserted in streets, between blocks of typical lateral dimension.^ 2.3 application to an existing urban situation As mentioned previously, travel across inner suburbs to and from 2 the downtown is the "urban situation" selected for facility insertion and evaluation. Fig.k shows a local Vancouver example of such heavily trav-ersed inner suburban areas. At present, there exists no highway conn-ection between the TransCanada (heavy band to the right of the 'box' in red) and the region's central business area. The absence of such a link has meant that large volumes of daily traffic travel through "east end" streets, en route to and from the downtown. Appearing in Fig.5 is the Venables-Prior alignment ("Corridor B"), at one time the designated location for a proposed east-west freeway. This freeway was to occupy, and of course require the clearance, of a block-wide 'swath' the entire length of i t s 3 mile route. In 1970 this alignment was abandoned in favour of one following railway lands (Fig.5, "C-1"); a routing which would, i f employed, create much less severe community impact. 'the total lateral distance shown is 680 feet, composed as follows: 20*122+66+122+20+122+66+122+20: in the sequence, lane/1ot/street/lot/lane/lot/street/lot/lane. The centre block is thus 264 feet wide. All houses are set back 25 feet. 2 since its function i s to control the undesirable consequences of otherwise legitimate (and frequently pleasant) actions, the facility being :t!inserted" might be termed an Intra Urban Device. 22. • ? if. TV. , • 1 ? \ • / V P -i If. i \ • -law ii « >? 'V L- rU KiJbOD Il.OOO •0.OO0 W ' ,. *-.,roc F7 '" " • • CfiOO \* (source: Cumulative Daily Traffic Volumes, f r Greater Vancouver Regional District, 1966) FIG.k: The inner suburbs of Strathcona, Grandview-Woodland and Hastings-Sunrise (red box) situated between the end of the Burnaby Freeway and the Central Business District. ro c x H i m r t O N PAftK * ""•en. ; l I s ! j FIG.5: 'Corridor B', Location of Test Facility (note: the area outlined in red i s the same as that shown in Fig.k) (map reproduced from N.D. Lea & Associates, "An Appraisal for the City of Vancouver of Transportation Systems and Routes Connecting the Brockton Point Crossing to Provincial Highways 401 and •+99"i 1968) Naturally, the existence of such an excellent route alternative is entirely fortuitous; i t cannot be counted upon. Far more typical i s the Prior-Venables situation, which would require the demolition of over 600 houses. For these reasons: because of its history and to the extent 2 of i t s typicality: the Union-Prior/Venables-Adanac alignment is an appropriate place to demonstrate the design strategy considered in this paper. 2.4 traffic diversion to "test facility" It i s assumed that the Prior/Venables corridor has been reconstructed as a depressed couplet, with two travelling lanes per direction. What would be the diversion to such a facility? Table 2 (overleaf) presents previously published^ estimates of 1985 peak hour travel desires to and from the downtown, assigned by the present author to a potential east approach route. With the exception of North Vancouver City and District estimates (which have been reduced by 1/3 on the assumption that no more than 2/3 of this area's downtown travel desires would manifest themselves in a Second Narrows Bridge routing) a l l figures are as they appear in the source document. from an "environmental" or "community impact" point of view 2 at the westerly end of the route, Union and Prior streets form the couplet; in the easterly portion, Venables and Adanac ^"Notes on the Burrard Inlet Crossing Project Approaches — C i t y of Vancouver; Examination of Alternative Concepts", Swan Wooster - CBA Engineering, October, 1968; diagram 3 TABLE 2: "P.M. Peak Hour CBD Person Trips. 1985" CBD to/from Outbound Trips Inbound Trips North Vancouver City & District kk07 503 Burnaby 6620 885 Coquitlam(s) 1725 0 New Westminster 275 0 Surrey 830 0 TOTALS: 13857 1388 Since what is shown in Table 2 are person—rather than vehicle— trips, two adjustments must be made to obtain an estimate of peak hour vehicular flow: deduction of an assumed transit share; and adjust-ment for an assumed passenger vehicle loading. On the assumption that the 1985 peak hour transit share will be somewhere between 1/3 and 1/2 of a l l person trips using an east approach route, between 69OO and 9200 outbound person trips remain to be carried by private vehicle. At an average loading of 1.3 passengers per vehicle, the number of vehicle trips must f a l l between 5300 and 7100. ordinarily, a third adjustment of the traffic forecast would be necessary, to take into account the non-passenger vehicles. In this case i t has been omitted since i t cannot possibly affect the conclusion which is about to be drawn. More refined estimation i s unnecessary since even the lower end of the range exceeds the nominal capacity of the test facility: 4000 vehicles per direction per hour: which of course sets an upper limit on possible diversion. As to the subordinate direction, p.m. peak hour vehicle trips cannot, according to this data, exceed 1400 per hour; with appropriate transit and load factor adjustments, the number will not likely exceed 1000. 28 CHAPTER 3 PERFORMANCE EVALUATION In respect of the areas of impact identified in Chapter 1, how successfully does the test facility perform? (That's the $64 question) What is the cost, and in particular, the relative cost, of this degree of absence of impact? (That's the other $ 6 4 question) The combined answers to these two questions will determine, almost completely, the fruitfulness of the present line of investigation. 3.1 community impact analysis (all factors except noise) In previously identifying the types of impact to be examined, no attempt was made to establish the importance of these, in either a relative or absolute sense. No attempt will be made now, other than to point out that i t would be perhaps difficult to maintain that each is of equal importance, and to suggest that among the most important almost 1 certainly will be "residential displacement" and "noise impact". With these exceptions, the importance and adequacy of the impacts selected, whether viewed individually or taken collectively, is left entirely to the reader's judgment. see, for instance "Grieving for a Lost Home" by Marc Fried in The Urban Condition. L. J. Duhl (ed.), Basic Books, 1 9 6 3 ; Mr. Fried begins: "For some time we have known that the forced dislocation from an urban slum i s a highly disruptive and disturbing experience . . . . Since we were observing people in the midst of a crisis, we were a l l too ready to modify our impressions and conclude that these were likely to be transitory reactions. But the post-relocation experience of a* great many people have borne out their most pessimistic pre-relocation expectations . . . . CF] or the majority i t seems quite precise to speak of their reactions as expressions of grief." 3.1.1 residential displacement: "destruction of housing and forced relocation of residents". As already indicated, this possibility has been designed away (in theory at least) by using existing street right of way. In practice, however, i f discontinuous streets must be employed then at least some displacement may have to occur. Fig.6, p.30, examines the worst case of route discontinuity likely to arise. It i s , in fact, the worst case possible where two conditions apply: (i) street right-of-way and block widths are 'standard' (as defined below) , and (i i ) any two streets may be joined to form a continuous route. As the figure shows, 132 ft i s the maximum amount of offset for misaligned street segments. (Because, of course, i f the r/o/w in the lower part of the drawing i s shifted to either the left or right, i t comes closer than 132 ft to one or the other of the possible connect-ing streets.) The importance of this fact i s that i t determines the limits of displacement due to the design strategy. A rough idea of the number of properties i t would be necessary to cross in order to connect two such misaligned segments can be gained by examining the position of the "s" curve in Fig.6 . Assuming a ko mph design speed and 33 ft lots, the connector would cross six properties. With 60 ft lots, the number 2 would be four, and so on. —————— 66-ft street r/o/w, 122-ft lot depth, 20-ft rear lanes; total block width 264 ft 2 note that only the centreline of the connector alignment i s shown in Fig.6 30. FIG.6: Maximum Discontinuity in Route Alignment (132 f t ) , Assuming 'Standard' Residential Street R/o/W and Block Widths note: design values of the connector alignment illustrated below are those identified in Fig. 7 , p . 3 2 <t I i 31 Fig.7, p.32% shows Venables St. at Windermere! the only problematic case of discontinuity on the study route. (For identification of the other cases of street offset and why they do not pose problems of residen-t i a l displacement, see Appendix III, p.97)# The connector alignment illustrated in Fig.7 would cause the displacement of only one house. This i s the only residential displacement necessary to construct the entire route. FIG .7: Connector Alignment for Discontinuous Segments of Route: 4b MPH design speed (design values): length of "s" curve, 5 0 0 ' ; radius of curvature, 561'; max. "e" value ,0k f t / f t source: p.336 and Table H-2, "Policy on Design of Urban Highways and Arterial Streets, 1973'V American Assoc. of State Highway Officials, Washington, D.C. 602/285 602/28y 602/292 P A R K E R ST - T F O 10 i f I W f t f l i i M O o 00 0J 33 3.1.2. visual intrusion: Three sources of community visual intrusion were earlier specified. A highway structure may: be unsightly in itself; block significant views; or afford views into adjacent residential prop-erty, thereby causing loss of privacy. It i s clear that the third item is not possible in a depressed 1 situation. And the second item is unlikely, since significant views will usually occur at the ends of streets (e.g. a view of mountains in the distance); and since (with the exception of design "A") no element of any of the designs rises far enough above grade to interfere with such views. However, in the case of "A", a viewer approaching the facility would be confronted with a wall 3 feet high and a canopy of vines rising a further 7 feet into the air. (Particularly at unbridged cross-streets where the canopy is continued through the former intersection, i t would become a dominant visual element. While technically a case of blockage— i f we assume mountains or some other desirable view in the distance—such combinations might be particularly attractive; and be therefore something to be sought rather than avoided.) I have been accused of setting up a "straw man" in specifying visual intrusion as an impact-type to be examined—i.e., as a deter-minant of the success or failure of my design. The objection, appar-ently, i s that the fact that the facility is below grade rules out the possibility of intrusion; that we know this from the start; and that, consequently, the test is a 'push-over'. But this seems to me to be missing the point. It is as though the design (or strategy of design) is being penalized for being too successful! (Since there would be no objection to including, as part of the test, a type of adverse impact which the design produced in at least 'respectable' quantities; but i f the design entirely avoids certain negative results, this fact cannot be pointed out!) Furthermore, i f we are to be precise in our use of the term "straw man", i t must refer, not directly to the capabilities of the design, but rather to the inclusion of something as bad that nobody actually holds tp be bad; and then claiming—as a positive achievement—the fact that the design avoids i t . As to the first item-- that the highway structure not be unsightly in i t s e l f — i t i s difficult to know how to approach the question of whether or not this is the case. Personal judgment packaged as bald assertion seems to be the only available 'method'. (Other than making this assertion, I would point out only, that in the design, the use of plant material i s intended to soften the visual harshness of the concrete structures being introduced into residential areas; this i s sufficiently successful, in my opinion, to preserve their "residential quality".) 3.1.3« traffic focal points and 'dumping': The elimination of inter-changes along the length of the route precludes the possibility of either of these problems occurring in any of the areas through which the facility passes. The definition of the study area as excluding "areas and effects beyond the terminals", avoids consideration of the effect of traffic 'dumpedJ on the downtown; nevertheless, one observation will be made: If (for environmental reasons, or because of insufficient ability on the part of the downtown street system to absorb the quantity of traffic that would otherwise be supplied) i t i s desired to exercise some degree of restraint on traffic entering the downtown, then a relatively simple means appears to be available for use. A restrictive downtown "We must not expect more precision than the subject-matter admits of", says Aristotle: (The Nicomachean Ethics. Book I, Section 3)> "Our discussion will be adequate i f i t has as much clearness as the subject-matter admits of, for precision i s not to be sought for alike in a l l discussions. . . . In the same spirit, therefore, should each type of statement be received .... i t is evidently equally foolish to accept probable reasoning from a mathematician and to demand from a rhetorician scientific proofs". parking policy—embracing the size, location and price of the downtown parking provision—is a destination-specific method of traffic demand  control; one that can be made time-specific as well. As such, i t i s a selective and presumably effective means of avoiding traffic over-supply to the downtown once a radial facility has been built. Of course, detailed study would have to take place before any such claims could be authoritatively made; but as a line of investigation i t appears promising, and could be taken up i f 'dumping' in the downtown context was seen to be a problem. 3.1.4 local access and parking; Vehicular access to property i s important for two reasons. It allows the delivery of goods and services. And i t enables proximate parking for residents and visitors. Access may be provided at either, or both, of the front or the rear of the property. If Fig.1, p.13, i s again consulted, i t will be seen that most of the designs allow local access streets at the property front; and that one of them ("C") additionally provides for parking on the street. If next the reader turns to the detail of Fig.3 which i s reproduced on p.36, he will note a "printer's f i s t " pointing to a car/truck situation at the centre of the drawing. This illustrates a 7 foot car 'squeezing' past an 8 foot truck which has mounted the curb to unload. There i s 17 feet available to accomodate these vehicles, the combined width of DETAIL OF FIG.3. P. 22 showing 7 ft car 'squeezing' past 8 ft truck which has mounted curb to unload. Total space available, 17 ft (}z+-11+5#) J<7 /*s-A f " / / / ! TIT i.i-J.i iU; i n u L-l UUid f. n A i) i ir aiL= which equals 15 feet.' Thus, design "A" permits local access and unloading, though not parking, at the property front. The latter function would have to be accommodated on side streets or, via rear lanes, directly on householders' property. In the case of earth-slope designs "B" and "D", rear lanes must serve completely the functions of servicing and access to parking since the entire street right-of-way is taken up by the arterial facility. Inspection of the more than 90 part or f u l l blocks in the study area reveals seven which have incomplete or non-existent access at the rear. (See sheets 1,2,5 and 6 of Appendix III). Many blocks, however, would require widening of rear lanes to bring 2 them up to an acceptable standard. Fig.8, p.38, shows a possible arrangement for local access and parking, suitable for use in conjunction with sloped-cut designs "B" and "D". Cross-overs for vehicles are provided at every second pre-viously intersecting street, but rather than simply running every second street right through (i.e. across both open cuts) the points of cross-over are staggered; this creates a T-junction pattern via the 'this figure reflects the dimensions given by the American Association of State Highway Officials for two types of design vehicle: "delivery trucks for service to homes" and "passenger cars". In Policy on Design of Urban Highways and Arterial  Streets. 1973. the Association remarks: "For design, a delivery truck is assumed to have . . . a=~ width between outer extremities of tires of eight feet." (p.410); and (p.268): "For purposes of geometric design, the design vehicle has physical dimensions . . . larger than almost a l l vehicles in i t s class." 2 assumed to be: 20 feet wide and paved rear lanes. This arrangement promises several benefits: increased safety; the discouragement of through traffic; the maintenance of ease of access to property and proximate parking. "Results of studies in both Europe and in the United States suggest that T-junctions may be desirable for connections between local streets . . . " (There are only three points of conflict in each T-junction i f "conflict" is taken to mean "the crossing of potential paths of legal vehicle movement".) Since local streets have by far 2 the highest costs in accidents, per mile driven, of any type of road , measures to reduce conflicts in the local access system would appear to be in order. As to the second point (the discouragement of through traffic) staggered T-junctions with rear-lane connections might be a signifi-cantly useful device for discouraging this sort of filtering. It will be remembered that the area of application of the facility is "inner suburban areas"—just those areas most subject to traffic filtering on a large scale. (In Fig.8: pedestrian ways are shown in orange; lanes and the travelled portion of local streets in yellow; the sloped outs in green and their paved portions in blue.) As may be seen in the diagram, the ends of discontinued streets can be used for other pur-poses, two of which suggest themselves especially: housing and mini-Research into Road Safety at Junctions in Urban Areas, Organisation for Economic Co-operation and Development, Paris, 1971, p .36. 2 Roger L. Creighton, Urban Transportation Planning, University of Illinois Press, 1970, Table 17, p.114. parks. The housing could be for either new residents or, i f there are any, for those displaced by facility construction. In this way the effect of displacement can be minimized; the residents perhaps being forced to leave their homes but not their neighbourhoods. Fig.9 (overleaf) illustrates a situation in which denial of local access would occur i f designs "B" or "D" were employed in a depressed couplet (the "halves" of which were one block apart) and a block such as that labelled "A" in the figure were thereby enclosed. Even though rear lanes exist, property demolition (2 units per 'isol-ated' block) would be necessary to provide access to a l l of the properties. The block shown in Fig.9 corresponds to that shown in yellow on the middle-left of sheet 10, Appendix III. (This also happens to be the point on the test route with the worst degree of street offset. Note that the lot widths (visible in Fig.9) and the building placement (sheet 10) , as well as the degree of offset, correspond generally to the case considered in Fig.7, p.32) Only two blocks on the route with this lane pattern would be enclosed. In ^ potential route locations where this pattern i s common, the obvious thing to do would be to locate the 'directions' of the freeway more than one block apart. This would avoid enclosure. unless access-ways, similar to the loop shown at the centre-right of Fig.8, were built Fig.9: "ACCESS VIA REAR LANES" 3.1.5 loss of street trees: (a factor not previously identified) No matter which of the designs is employed, complete loss of existing street-trees i s unavoidable since each scheme utilizes the entire right of way for essential purposes other than planting. If loss of trees i s seen to be a problem, replacement trees can be installed on private property at public expense (i.e. this cost could and should be internal-ized in the cost of the transportation facility, since i t is the facility which has created the problem). As the presently existing trees on the test route tend to be small, substitution would in this case tend to be satisfactory and complete. 42. 3.2 the environment for driving Table 1, p.19, which compares the design features of six cross-sectional designs, l i s t s three items which are thought to bear on the quality of the driving environment: the "openness" of the cut; whether vegetation is visible; and whether emergency stopping lanes are provided. The first two items may be classed as affecting the visual quality of the driving environment. It must be pointed out, however, that in the case of design "A" these desirable features may conflict with each other. That i s , even though the canopy rises 25 feet above the surface of the travelled way, i f the hoops are densely spaced the effect may be to reduce the feeling of openness. This could be avoided by spacing the hoops more widely, thereby creating a balance between a feeling of openness and a sense of enclosure. Where the vine t r e l l i s i s eliminated completely—as i t would be, periodically, throughout the route—open sky would come within the driver's available cone of vision (see lower portion of sketch on p.45). A supplementary means of improving aesthetic quality i s to line the retaining walls with coloured ceramic t i l e . By varying the treatment of these elements over the length of the route, driving in the cut can be 1 made to be more visually interesting. While the precise nature of the cut's interior design i s an archi-tectural problem, perhaps enough has been said to indicate that there are ways to achieve an acceptable standard of visual quality in what might be termed "open tunnels". 1for an account of the desirability of varied treatment, see Kevin Lynch, "The City As Environment", Scientific American, vol.213, no,5 Turning now to the "earth slope" designs, each of "B", "D" and "F" i s considerably more open than any of the designs which are vertically retained. As Fig.10 attempts to show, when furnished with large-scale plant material*, sloped cuts could provide attractive driving environments Fig.10 also shows the cone of vision available to drivers at h5 mph. At this speed, the driver's eye would focus on a point travelling 1^00 ft ahead of his car and peripheral vision would exist in a cone extending p 32#° from the focal line. The significance of this i s simply that the driver's attention i s , in fact, focused on the road far ahead of him and not on the sides of the cut. So although the cut does constrain his field of vision, i t does so only peripherally. Even peripheral vision i s constricted only on the sides, not in the plane extending forward at an angle of 32/ze frpra the focal line. (See sketch, p .45). A further point to note is that.the apparent height of the wall on top of the slope will diminish with distance. At distances close-in to the moving vehicle,the walltop will appear to be high though vague; its apparent height will decline as i t comes more sharply into focus. As i t s apparent size shrinks, a proportionately larger amount of sky will be visible. 'the assumed operating speed of the facility. (Speed i s considered in the section on noise). 2 interpolated from speed/focal length/angle of vision relationships quoted in The Freeway In The City: Principles of Planning and Design. Urban Advisors to the US Federal Highway Administrator, USGPO, Washington 1970. (The faster one goes, the further ahead the eye focuses and the narrower the horizontal angle of vision. Thus at 25 mph one's field of vision extends horizontally about 50° to either side of the line-of-sight between the eye and i t s focal point 600 feet ahead; while at 60 mph, the focal point lies 2000 feet ahead and the angle of vision shrinks to less than 2 0 ° . ^5. L A N E 1 To conclude: (1) earth-slope designs are considerably more open than the retained variety. (2) when furnished with large-scale plant material, they can be made to be visually attractive environments for driving. (3) The field of vision of a driver in the cut would not be severely restricted by the road's depressed location. i I r 3.3 noise impact analysis 3.3.1 development of a criterion of impact: The first task in determining whether a noise impact would *in fact* exist is the development of a meaningful impact criterion. In order to establish a criterion, i t will be necessary to discuss something of the phenomenon of noise, its measurement and effects. Perhaps the first thing to note is the conventional method of noise measurement: by means of the decibel scale: a logarithmic scale which is one at the threshold of hearing, and 140 at the threshold of pain. Each interval of ten decibels indicates a level of sound energy ten times greater than before.... A noise twenty decibels higher than another has one hundred times the energy of the latter, and so on.^ Each of the above-described intervals i s , however, experienced 2 by the human ear as being only roughly twice as loud. To subjectively calibrate the scale, i t is essential to relate i t to noise sources, of various intensities, in our ordinary experience. Reproduced (Fig.11, p.47) i s Beranek's chart of the comparative inten-3 sities of various common sounds. It should be noted that the values shown in Fig.11 are in "A" weighted decibels (dBA)—a measure of sound which takes into account the ear's decreasing response at high and low frequencies. Kevin Lynch, Site Planning. MIT Press, 1962. 2Ibid. see also: Effects of Traffic and Roads on the Environment  in Urban Areas. OECD, Paris, 1973. ^Leo L. Beranek, Noise, Scientific American, December 1966, vol. 215, no.6. /+ the "A" weighted decibel . . . is an adequate objective measure providing a reasonable correlation with subjectively determined rankings. Effects of Traffic and Roads on the Envir- onment in Urban Areas, OECD, Paris, 1973. 47. THUNDERCLAP ROCKET AIRPLANE MACHINE' STREET NOISY OFFICE AUTOMOBILE CONVERSATION HOME QUIET OFFICE • WHISPER ZERO LOUDNESS FIG.11 HI III I Hli'i lliiill I I II lliiliill II Willi IIIIIIIII lliilllll 11 111 ill II m 'I'll ! mum I! iiiim I i iimi mu iiiiiiiii M i l nil! iiiiiiiil lliiliill 11 i i i iiill I H i l l illliilll Nil WIN WWII HI mil IIIIIIIII li i I Hill! I ! Illlli iill Mil Willi Iiiiiiiii lliiliill Mi'iilH i t i l l Illliilll IliHIIH ilill I iii lliiill I II [ M i l ! ; ! I I i l l ! ! ! 20 -10 0 10 ,20 30 40 "Intensity of various common i llllili 70 nil! Illll iniii 11 ninii 11 ' III • I NOISE (dBA) sounds' ^(Ber^nekT iiiuii 1201 So far we have established that noise—as perceived by an average human listener—may be accurately measured in A weighted decibels; and that each increase of 10 on the scale indicates a noise 100$ louder than before. But while direct A weighted meter readings are adequate to describe instantaneous levels, statistical description of a series of instantaneous measurements is required for most purposes, since most sources (including traffic) vary over time. A common means of communi-cating the temporal incidence of peak levels makes use of the designa-tions L ^ Q and L ^ . One or more of these "level designations" when used in conjunction with appropriate dBA values indicates the highest noise level exceeded a certain percentage of the time. In the case of L ^ Q , i t i s the level exceeded most (i.e. 90$) of the time. In the case of LJ-Q, i t i s the median level: the level in respect of which half of the measurements are higher and half are lower. And finally, in the case of L 1 Q , i t is the level exceeded only 10$ of the time. In resid-1 ential areas in Greater Vancouver, the average daytxme levels are 2 currently as follows: L 9 0 42 dBA L 5 Q . . .51 dBA L 1 Q . . ... 64 dBA illustrating that there i s more than one "peak" level and that a "temporal incidence" specification is essential for the correct inter-pretation of figures purporting to represent 'the noise level'. Naturally, the same caveat applies to noise standards such as those displayed in Table 3, p.49. If the reader considers carefully the contents of the table, he will note that—despite the fact that the standards "represent an expert assessment of tolerable noise levels"^— there is considerable variation in their stringency. They range, in fact (for those that use L 1 Q as the measurement base) from 56 to 70 dBA; a range of standards whose higher end is almost three times as loud as its lower!^ 1 i.e. average values of L Q n L,_n and L. for residential areas as a class 2 A. Community Noise Survey of the GVRD, by Barron and Strachan, Consulting Acoustical Engineers, Vancouver, 1971• ^in the words of the OECD report from which the material in Table 3 i s taken 4 Table A-1, "Relation Between the Difference in Noise Level of Two Noises and their Relative Noisiness as Judged by Average Listeners", in Highway Noise: Measurement, Simulation, and Mixed  Reactions, [US] National Cooperative Highway Research Program Report 78, Highway Research Board, 1969. •nose ! STANDARD? HOW MEAEUHED? MAXIHUM AHUMT Motes *nd Uhrti: r v e t t o n s Land Doe o r typo of ar e a ; Scholes L-10 i n t e r i o r 70 dilA "They r o c c f i . i m that such i n d averaged (1 a fruai * n o l a t exposure let l e s s Sargent over a the b l d g . I han t h a t o b t a i n i n g «t weekday facade) euny e x i n t l n g d w e l l i n g s period a d j a c e n t t o o i i i n roada and i 6 a.«« to t h a t p r o p l e l a e x l f l t l n g | .12 eildnlght h o n t i n g excooed t o n o i s e l e v e l o up t o s.'id I n c l u d i n g j . • -. ' ' 70 d i A »:•« u n l i k e l y t o bo < . eerioui;'.y d i e n i i t i a f i e d w i t h ' ;• • . t r a f f i c noma. rhey do not | '; -.Claim, howevor, t h a t ao. L-10 r o f 70 dlJA r e p r e s e n t s q u i e t ! ' '•<••'•,',• c o n d l t l o n u o r even c o n d i t i o n s -r of no d i a e a t l s f a c t i o n . " r e s i d e n t i a l a r e a s . Oordon | i t a l t ( a l s o ' recooxaended fby i K a r m a l l n k i f o r use In ! proTinea o f t O n t a r i o ) L-10 E x t e r i o r 55 « i n a d d i t i o n , t h e y r e c o m m e n d (day) t h a t ^he tnet-n n o i a e l e v e l , or L -50, u h o u l u not exceed 51 ddA the e m b i u n t l e v e l by o o r a ; : ( n i g h t ) than 9 d B A - s t a n d a r d b a a e d o n speech it s l e e p i n t e r f e r e n c e e f f e c t s ©f noiae r e s i d e n t i a l areas) U 1 KRANCS L-50 a o u « si a o o a +> u <H U I n t e r i o r , *»0-**5 corre$p^nue t o a 60 dBA ' dBA l e v e l oc the facade; Day / . t i e Inc c.a;ied by 5 daA i n _v ; :• !.: a d m i n i s t r a t i v e aad ; i . commercial b u i l d i n g s E x t e r i o r <60 drlA 6O-70 dBA %\". ->70 dBA l i v i n g a r e a s a d m i n i s t r a t i v e a r e a s s c h o o l s " p l e a s a n t a r e a s " ."areas where • s p e c i a l s t e p s w i t h regard t o I n s u l a t i o n iuwo t o be t a k e n " "areaa where housing c o n s t r u c t i o n s h o u l d not be p e r m i t t e d " JAPAN L-50 E x t e r i o r 50 dBA "zones used f o r d w e l l i n g s o n l y " 55 dBA "areaa f a c i n g t w o - l i n e r o a d s " 1 60 dBA "areas f a c i n g roads wldt.' th;ui two l a n e s " • t . • ! £0 dEA "zones c o n t a i n i n g con* • , o e r c i a l ruid i n d u s t r i a l uses ae w e l l aa a c o n s i d e r a b l e .' nuaber of d w e l l i n g s " ,: 65 dBA sane type of area aa ie t o e d l o t o l y abo»», when " f a c i n g r e a d s " ir-axirca f o r d i f f e r e n t t y p e s of r e s i d e n t i a l nones .U.S. • F e d e r a l ; Highway ' A d a i n l a -: t r a t i o n L-10 E x t e r i o r - i n t e r i m ntwidords (as of Aj.-I) 1972) 60 dRA 70 dlW "porks and open spaces whore q u i e t * neea l a of primary i mportance" " r e s i d e n t i a l a r e a s , h o t e l s , ffotels.sehools l i b r a r i e e , h o a p l t a l s , rec rf- u t l o n a r e a a , p l a y g r o u n d s , a c t i v e s p o r t s a r r a s Hi p a r k s " Of these standards, "Only that proposed by Scholes and Sargent appears to be directly based on a compromise between the rival constraints of low road construction costs and environmental quality". This fact is sufficient to eliminate from consideration their standard as a possible criterion of impact; for i t is clear that the presence or absence of impact must be determined on the basis of "desirable" rather than "comp-romise" standards. (For supporting considerations in this regard, see entry under "Notes and Observations", Scholes and Sargent, Table 3«) On the other hand, the standard proposed by Gordon et al seems excessively strict, not in terms of what i t is trying to achieve, but rather in the necessity of i t s specified maximum in doing so. The objective, evidently, is the avoidance of "speech interference" in the interior of residences during the daytime period. According to a noise laboratory which did pioneering work in the concept and measurement of 2 "speech interference level" , Outdoor traffic noise of 65 dBA will permit indoor speech communication, in a quiet voice, at 5 to 10 feet; and in a normal voice, at 10 to 25 feet.^ This seems to me, and I assume to the reader, to be an entirely adequate level of speech comfort. Effects of Traffic and Roads on the Environment in Urban Areas, OECD, Paris, 1973. 2 the firm is Bolt, Beranek and Newman Inc., for an account of their specially devised "Speech interference level decibel" (SILdB) see: "Noise", Leo L. Beranek, Scientific American, December, 1966. ^these "voices" are part of the progression: "quiet"; "normal"; "raised"; "shouting" 51. Let us therefore reject the "Gordon standard" as a reasonable criterion of impact, just as we did the standard of Scholes and Sargent; the one because i t is too stringent, the other because i t is not stringent enough. If we do so, we have narrowed the range for an acceptable c r i -terion to between (let us say) 60 and 65 dBA at the L ^ Q level. Now for the final step. I believe we have accumulated some very good grounds for the selection of 65 dBA as the sole criterion of impact. Perhaps the most prominent of these is what I consider to fce this level's complete lack of serious interference with interior speech communication. Secondly, the fact that an L ^ Q of 6k dBA i s the currently prevailing noise level in Greater Vancouver neighbourhoods. Thirdly, in respect of outdoor speech communication, that traffic noise of 65 dBA permits speech to be transmitted in a normal voice at distances of 2 to 5 feet; suff-icient, in other words, for two persons to carry on a normal conversation 1 while walking side by side in the open air. Highway Noise: Measurement, Simulation, and Mixed Reactions, [US] National Cooperative Highway Research Program Report 78, Highway Research Board, 1969; Table 7. V 52. 3.5*2 degrees of noise impact, defined: In selecting a criterion of impact, care was taken to choose the single value which seemed most appropriate for the purpose. But no matter how well-founded a criterion, i t cannot properly be used as a 'magic dividing line* between zones of black and white. Rather, the threshold of impact should be considered to be a zone, centering on a significant value but extending some distance above and below i t . On the lower side, an appropriate distance would seem to be half-way between the significant value (65 dBA) and the first point about which we have no difficulty in saying that an impact definitely does not exist. In a parallel fashion on the higher side, a value representing the first point of "definite impact" would be chosen and the impact threshold extended half-way toward that point. If this is done and the values 60 and 70 dBA chosen, the threshold of impact will extend from 62.5 to 67.5 dBA at the L^Q level. Fig.12, on the page following, extends this process to define degrees of negative impact ranging from the marginal, at the impact threshold, to the severe, at about 80 dBA. Noise intensity is shown in generalized bands around central defining values; the relative noisiness of these bands i s shown in relation to the highest noise level which avoids impact (60 dBA). (The bands centering on 65,70,76, and 80 dBA are, respectively, 1#, 2, 3 , and k times as loud as the highest "no impact" level.) Note that the band labelled "serious impact" is about that level (75 dBA) which requires outdoor speech to be conducted in a raised voice at 1 to 2 feet. FIG.12 Degrees of Noise Impact, Defined note: relative noise intensity is shown graphically as follows: the band around 60 dBA in 1C# tone; the 65 dBA band in 15# tone; 70 dBA band, 20% tone*...and so on, in proportion to the loudness of the higher bands in relation to the lowest band. data source: Table A-1, "Highway Noise: Measurement, Simulation, and Mixed Reactions". 3.3*3 noise simulation: selection of a method; some difficulties in application method: a simplified analytical form of a computer simulation model developed by the firm Bolt, Beranek and Newman for the Highway-Research Board. On the development of their model, the authors state:'' Following the analysis of noise measures and of measured noise for various vehicles of various types, a computer simulation model was evolved which allows the engineer, designer or researcher to set the following conditions, average vehicle speed, number of lanes, density or flow of traffic, proportion of trucks to cars, and distance to the measurement site. Given those conditions, in any possible combination, computer estimates are made which are extremely close to those actually read from the meter. This simulation model enables the prediction of what vehicle noise will be for any existing or planned highway situation for freely flowing traffic. The last sentence quoted above is slightly misleading since the model does not allow for "the variable effects of shielding structures 2 and topography." However, a chart is provided to allow correction due to various highway configurations, and discussion of this will be taken up in a later section. As to the simplified analytical form of the model (p.55) i t is accurate to within 2 dBA of the answer obtained by the more detailed method; and is valid for passenger cars on a level highway at traffic flows above 1000 vehicles per hour.^ 1 Highway Noise: Measurement, Simulation, and Mixed Reactions. Highway Research Program Report 78, (US} Highway Research Board, 1969, p 2 Ibid., foreword Ibid., p.7 L = 1 0 l o e „ , g X , ' Q ° +201og,„K a = l O l o t - , , , 9 - 10 1 o g 1 0 d + 2 0 1 o g 1 0 F + 20 in which q = traffic volume flow, in vehicles per hour; d = distance, in feet, to pseudo-lane; and F"= average traffic speed, in miles per hour. Appearing i n the sketch below i s "pseudo-lane" location for a two lane roadway, defined i n relation to observers both to the l e f t and to the right of the actual roadway lanes. (The area i n darker tone overlapping the actual lanes i s the pseudo-lane.) ::\ it I i I i i i I A C T U A L LAMBS \< P\< M »• < <*\ . 1 -;\ Ti! & !, I l l 1 » I f t " ' Ibid.. p.13» the "pseudo-lane" i s a hypothetical single lane to which a l l t r a f f i c (and consequently the origin of a l l noise) i s summar-ized, "This single-lane-equivalent can be considered as a hypothetical lane carrying the total flow (ignoring the overlap of real vehicles). It should be considered as located at a position displaced from the closest lane to the observer by a distance equal to the square root of the number of lanes times the lane width. For example, on a four-lane highway the effective pseudo-lane would be at the location of the second lane closest to the observer." 56 application of the method; Since (from Chapter 2) potential peak hour traffic for the eastbound direction of a radial freeway i s in excess of the nominal capacity of the test facility, we should first simulate the capacity condition in the dominant direction. There is some difficulty in making valid correction for the close-at-hand shielding effect of the test designs. This will be discussed shortly. In the meantime, preliminary calculations will be made to determine the level of noise exposure which would exist i f there were no reductive effect due to the highway's depressed location or to the existence of walls which rise above the level of surrounding grade. Exposure (thus defined) will be determined at the sidewalk midpoint and the building facade. For the purpose of these and subsequent calcula-tions, buildings are assumed to be set back 20 to 25 feet from the property 1 line or a total of 5k lateral feet from the noise source, the centre-line of the pseudo-lane. (The distance between the noise source and the middle of the sidewalk i s 29 lateral feet.) Noise predictions will be made for four situations; Situation #1 'facility operating at maximum capacity in dominant direction (~4000 veh/hr) 'speed of flow, 30 to 35 mph (note: the natural or unrestrained speed of,,flow for this volume of traffic is identical: 30-35 mph)v'~ 'vehicle density: 120 per mile i.e. 22)4 feet 2 a l l references to "unrestrained speed" based on speed/volume relationships exhibited in Fig.3.38, p.62, Highway Capacity Manual, Highway Research Board, Washington, 1965 57. situation #2 . facility operating at three-quarters capacity in dominant direction (1500 veh/lane in each of two lanes) . speed of flow: 40 mph (note: the unrestrained speed for this volume is 41# mph) . density: 80 veh/mile situation #3 . facility operating at half-capacity in dominant direction (1000 veh/lane in each of two lanes) . speed of flow: assumption (a): posted 35 driven 40 assumption (b): posted 40 driven 45 . the unrestrained speed for this volume: 47)4 . density: assumption (a): 50 veh/mile assumption (b): 45 veh/mile situation #4 . facility operating at one-quarter capacity in dominant direction (500 veh/hr/l in each of two lanes) . speed of flow: assumption (a) posted 35 driven 40 assumption (b) posted 40 driven 45 . unrestrained speed of flow . . . . 54 . density: assumption (a) 22 veh/mile assumption (b) 21 veh/mile On these assumptions, noise 'exposure' at both building facade and sidewalk have been calculated (see Appendix II for details). Results are displayed graphically in Fig.13 (p.58) and in tabular form on the page following. FIGV13,: Gross Estimate* of Highway Noise Exposure at Two Points, L_ n Level ^ #2 #3(a,b) #4(a,b) Tr a f f i c ' S ituations'—y notes: , * i . e . does not take into account reductive effect of depression and solid barriers; therefore does not represent net amount of exposure * author's c r i t e r i o n of impact TABLE 4: "GROSS HIGHWAY NOISE" * 'exposure' situation at sidewalk* at bldg. facade* #1 L 5 0 71.5 dBA 68.8 dBA L 1 0 73.1 70.5 #2 L 3 0 72.0 69.4 L 1 0 74.0 71.4 #3 L 5 0 a 70.3 a 67.7 b 7 1 . 3 b 68.7 L 1 0 a 72.6 a 70.0 b 73.8 b 7 1 . 1 #4 L 5 0 a 67.3 a 6 4 . 7 b 68.3 b 65.7 L 1 0 a 70.5 a 67.9 b 71.5 b 68.9 * Note!! This is not an estimate of actual noise exposure at either of the two points, but rather a calculation of what the exposure would be i f there were no shielding. 60. The purpose of Fig.13 and Table 4 is to demonstrate the worst  possible noise exposure, at two positions relative to the highway., assuming the range of conditions which constitute the four "traffic situations". Since we have, for this calculation, assumed a total absence of shielding effect, we can be absolutely certain that actual exposure from the highway will not be greater than the amounts indicated in this table and figure. How disruptive i s this "worst possible" case? Fig.13 shows the L^Q curve at the building facade 'tracking' 70 dBA—which, i t will be recalled, is the standard proposed by Scholes and Sargent. As quoted in Table 3 , "people in existing housing exposed to noise levels up to and including 70 dBA are unlikely to be seriously dissatisfied with traffic noise." However, i t is not claimed that this level "represents quiet conditions or even conditions of no dissatisfaction." Possible exposure at the sidewalk lies between 70 and 75 dBA— approaching, in situations 2 and 3(b), the higher level. Since outdoor traffic noise of 75 dBA requires outdoor speech communication to be conducted in a raised voice at 1 to 2 feet, in the absence of effective shielding, impact at the sidewalk will be serious. Before exploring the actual degree of noise shielding which can be expected, two final points will be stressed. Firstly, that 70 to 80 2 decibels is the level of noise given rise to by a busy arterial street —a;fact which puts the "worst possible" performance of the facility 'Table 7, "Noise Criteria for Speech", in Highway Noise: Measurement, Simulation, and Mixed Reactions, p.18. 2Kevin Lynch, Site Planning Handbook. MIT Press, 1962, p.99, gives the level of a "busy street" as 70 to 80 decibels while Beranek (in the chart reproduced as Fig.11, p.47) shows the level of a"street" as 80 decibels. 61 into some perspective. And secondly, that the results of the demon-stration apply (of course) equally to each of the test designs. shielding effect of "retained test design; determining exposure  at the sidewalk mid-point and the building facade The difficulty, mentioned earlier, of adjusting preliminary calcu-lations of exposure to take account of the reductive effect of highway configuration will now be explored. Reproduced on p.62, as Fig .14, is a chart intended for use in making this sort of correction. On its develop-1 ment, the researchers state: Often a highway in an urban area is built on a grade above or below the elevation of the surrounding property. Such differences in grade provide some shielding of traffic noise, reducing the noise levels at the adjacent property. Computation of shielding on a theoretical basis is extremely complicated and applies only to a single source-receiver distance. In order to obtain design data for practical use in highway design, measurements of noise produced by traffic under conditions of elevated and depressed grades where the nominal change of elevation is typically 20 feet have been taken. All measurements were made adjacent to various 6- or 8-lane divided freeways, where lane widths were nominally 12 f t . These data were used to derive the design chart shown in Figure 0*0 • This figure indicates the de-crease in noise level with distance expected for the configurations described as well as for an on-grade situation. The reason for the chart's inapplicability in the present case is rooted in its empirical nature: since " a l l measurements were made adjacent to various 6 - or 8-lane divided freeways", measurements used to derive "distance to centre-line of lane in feet" (horizontal axis) will incorporate standard amounts of space for outer separations. p.15. Highway Noise: Measurement, Simulation, and Mixed Reactions, 62. FIG;14 Ncjete Reduction Provided by Various Highway Configurations source: Fig.7, p.15, "Highway Noise: Measurement, Simulation, and Mixed Reactions", Highway Research Board, 1969 63. This is important. It accounts for the lack of reduction, over and above that provided by distance alone, by a vertical cutting at distances of up to about 30 feet. As the sketch below illustrates, a receiver located at 1 30 feet of lateral distance from the point of transmission is s t i l l in a direct line of exposure to the noise source; there is thus no shielding effect. In the author's designs, barrier placement is more effective. Not only is line-of-sight blocked (between source and potential sidewalk receiver—see Fig.15, overleaf); but only 3 feet separate the vertical wall from the near lane-edge in the "retained" test design. This is significant because barrier effectiveness increases as the barrier i s 2 moved closer to either source or receiver. in Policy on Design of Urban Highways and Arterial Streets, 1973. Table H-10 ("Effect of Noise Control Measures on Sound Levels, Six-Lane Freeways . . .") the American Association of State Highway Officials assumes noise barriers to be 30 feet from the edge (near) of the pavement. I have taken this as a guide to typical minimum separations between noise source and barrier for highways of the existing type. 2 Kevin Lynch, Site Planning Handbook, MIT Press, 1962, p.100. FIG.15: Area Free of Direct Exposure to Noise* 64. note: the T-shaped markings1 at the sidewalk represent persons six feet t a l l In one other respect there is an absence of parallelism necessary to consider. The design chart is based on a 20 foot change in grade, whereas the author's designs measure 15 feet from the finished surface of the arterial way to the level of surrounding grade. On the other hand, the walls in each design extend above this level. The question arises: "Can this extra portion compensate? Can i t be counted part of the 'effective depth' of depression?" There are two reasons for thinking so, the first of which appears in Fig.16, p.66. The solid line (representing the line-of-sight between a point assumed to be the position of the noise source and the top of the barrier) intersects with a plane (extending vert-ically, 5 feet away and parallel to the cutting) at an elevation of +13 in the case of "A" and +10 in the case of "B". This means that, noise tending to 'plume', there will be less noise exposure where 3 of the 18 feet of depression are "effective" rather than "actual". (This "at least equally effective" conclusion is confirmed by AASHO's Table H-10, which shows a 6 foot high barrier in conjunction with a ground-1 level roadway to be consistently more effective as noise control meas-ure than location of the road in a 10 foot depression.) Assuming only equal shielding effectiveness, the depth of the vertical cut will be effectively 18 feet (15+3); and the sloped cut: 19 feet (15+4). But we saw, in the graphic analysis of Fig.16, that above-grade walls have greater effectiveness per unit of vertical dimension than does i.e. measured at four distances (100-400 feet) from the near edge of the travelled way. Policy on Design of Urban  Highways and Arterial Streets, 1973. American Association Of State Highway Officials, Table H-10. t-r-T"7 ' | I 1" t--r -~|-_|_ 1 I ! i ; 1 1 t — t — i -IS' •Effective Depth' of Depression "J. 1 8 ' DEPRESSION T ON o\ 67. a lowered roadway. We must conclude therefore that the effective depth of depression of each of the author's designs at least equals and probably exceeds the actual 20 ft depression of the highways which form the empiri-cal basis of Chart Ik. What are the above considerations worth in terms of reduced dBA values at the sidewalk? For the vertically retained design the upper limit of possible reduction i s presumably defined by an extension of its curve in Fig.14 so that i t continues to parallel the "on grade" curve, right down to the lower end of the distance scale. If this i s done, the maximum reduction which is indicated at 29 ft (i.e. the reduction over and above that for the on-grade situation) i s about 7 dBA. For the mini-mum reduction likely, we will assume half of this maximum amount (3*5 dBA). For the sloped-cut design, a similar procedure applied to i t s curve yields maximum and minimum values of -k and - 2 dBA, respectively. These estimates are so close that a single value, the median value of - 3 dBA, will be taken to be the reduction at the sidewalk due to shielding. At the building facade, determining net exposure i s less problematic; the Chart can be used in i t s unmodified form. A difference of 11 decibels is indicated between the intensity of noise at 29 f t , where there i s no shielding (the on-grade curve); and noise intensity at 3k f t , where shield-ing exists (the curve for the vertical cut). Since the middle of the sidewalk is located 29 ft from the noise source, previously-calculated sidewalk values (Table k) may be reduced by 11 dBA to obtain net exposure at the building facade. By the same procedure, i t can be determined that exposure at the facade from a highway in a sloped cut will be 8 dBA lower than gross sidewalk levels. Tables 5 and 6 (pp.69-70) show final estimates of noise exposure at the two critical points, based on these corrections. 68. These are the major conclusions of the impact analysis for noise: vertical design (1) on the assumption of maximum shielding effectiveness, exposure at the sidewalk (ranging from 63.5 to 67.0 dBA) will f a l l entirely within the threshold of impact, i.e.^marginal impact) (2) on the assumption of minimum shielding effectiveness, exposure at the sidewalk (ranging from 67.0 to 70.5 dBA) will f a l l within the lower half of the definite impact range, ^definite impactj (3) L ^ Q exposure at the building facade (ranging from 59*5 to 63.0 dBA) will be at or below the impact threshold, jjio impactj sloped design (k) on the assumption of 3 dBA shielding effectiveness, L 1 Q exposure at the sidewalk (ranging from 67.5 to 70.8 dBA) will f a l l entirely within the lower half of the definite impact range, ^definite impactj (5) 1 1 0 exposure at the building facade (ranging from 62.5 to 66.0 dBA) will f a l l entirely within^the threshold of impact, ^marginal impactj TABLE 5: VERTICALLY RETAINED DESIGN: Calculated L-10 Highway Noise Exposure at Sidewalk and Building Facade traffic A @ sidewalk, assuming max. @ sidewalk, assuming min. @ building facade situation no. shielding effectiveness* shielding effectiveness** #1 66.1 dBA 69.6 dBA 62.1 dBA #2 67.0 70.5 63.O #3a. 65.6 69.1 61.6 #3b 66.8 70.3 62.8 #4a 63.5 67.0 59.5 #4b 64.5 68.0 60.5 * iwe. a reduction of 7 dBA from "gross sidewalk levels" (see Table 4, p.59) ** i.e. a reduction of 3.5 dBA from "gross sidewalk levels" TABLE 6: EARTH SLOPE DESIGN: Calculated L-10 Highway Noise Exposure at Sidewalk & Building Facade traffic L-10 exposure at L-10 exposure at situation no. sidewalk * building facade ** #1 70.1 dBA 65.1 dBA #2 71.0 66.0 #3a 69.6 6<+.6 #3b 70.8 65.8 #4a 67.5 62.5 #-+b 68.5 63.5 notes: * shielding effectiveness at sidewalk assumed to be 3 dBA, i.e. a 3 dBA reduction from "gross sidewalk levels", Table k ** assumes 8 dBA reduction from "gross sidewalk levels"; reduction due to increased distance (+25 ft) and shielding effect of open cut TABLE 7: VERTICAL CUT; Combined. L-10 Exposure at Sidewalk with Both Portions of Facility Operating Simultaneously; Various Conditions of Speed & Flow both freeway theoretical L-10 theoretical L-10 directions in exposure at sidewalk exposure at sidewalk combined exposure ** situation no.: from nearside facility from farside facility* 1 66.1 - 69.6 44.1 - 47.6 no increase 2 67.0 - 70.5 45.0 - 48.5 no increase 3 66.2 - 69.7 44.2 - 47.7 no increase 4 64.0 - 67.5 42.0 - 45.5 no increase * the exposure position i s 296 ft from the farside noise source; noise i s reduced 22 dBA (from its level at 29 ft from the source) by travelling the intervening distance to the receiver. See Fig.14, p.62. ** there is no increase because, in each case, the higher of the two amounts being combined exceeds the lower by more than 10 dBA 72. combined exposure from two sources The analysis has so far proceeded on the assumption that a single two-lane facility i s the source of highway noise. In fact, the design calls for two such facilities separated by the width of a 'standard' city block. There i s a question, then—with this degree of closeness ini spacing—whether combined exposure from two facilities will exceed that of a single facility operating alone. This question was examined in relation to the sidewalk position. Before discussing the results, i t should be noted that in determining combined exposure, decibel levels cannot be added directly; rather, they must be compared to determine by how much the higher level exceeds the lower. If the higher exceeds the lower by 10 dBA or more, combined exposure will not exceed the exposure which would occur from the louder source alone.^ As Table 7 on the preceding page indicates, in every case exposure at the sidewalk from the more distant facility would be 22 dBA lower than exposure at. the same point from the nearby facility. Thus, in no case will farside exposure be capable of affecting 'nearside* levels. 264 feet between rights-of-way ^Table 3, "Addition of Decibels", Highway Noise: Measurement,  Simulation, and Mixed Reactions FIGURE 17 Combined Exposure at Sidewalk from Two Sources (located one block apart) Operating at Maximum Noise Generation note; 65 dBA (outdoor traffic noise) permits outdoor speech communication in a normal voice at 2 - 5 75 dBA permits outdoor speech communication in a raised voice at 1 - 2 ft -combined exposure(67»0 - 70.5 dBA) would not exceed exposure from the nearside facility alone -worst exposure i s thus in lower half of "definite impact" range 74. Fig.17, p.?3» indicates that traffic noise exposure at the sidewalk would cause some interference with speech communication. The degree and seriousness of interference depends entirely on actual noise exposure. It will be recalled that two assumptions regarding shielding effectiveness were made: - 7 and - 3 . 5 dBA. With a shielding effectiveness of 7 dBA, exposure will be 67 dBA at the sidewalk and there will be practically no interference. If shielding i s less effective, L^^ exposure could go as high as 70.5 dBA„(i.e. to a level whose noisiness i s 50% greater than that permitting speech in a normal voice at 2-5 f t ) . This would cause more serious interference,although i t should be noted that the level which requires outdoor speech to be conducted in a raised voice at 1-2 ft i s 50$ greater again.^ Table A-1, "Relation Between The Difference In Noise Level Of Two Noises And Their Relative Noisiness As Judged By Average Listeners", Highway Noise: Measurement. Simulation, and Mixed Reactions 3.4 financial cost The question of financial cost must be addressed (to at least a limited extent) because i t i s not sufficient to have shown that i t is possible to insert—in existing urban fabric, in a non-intrusive manner-1 a facility which adequately performs a valid transportation function. Nor i s i t enough to have shown that such 'null' or ••minimal" impact freeways, when inserted in heavily-trafficked corridors, will act to restore the quality of traffic-degraded environments. To demonstrate conclusively the social utility of the present approach requires an evaluation of benefits and an accounting of costs. The fact that the essence of the present approach consists in avoiding social costs by (where necessary) incurring financial costs, makes the question of financial cost accounting a l l the more important. "O/C, IT Wot{Ky,. i.e. the bypass function (without any collector/distributor element) in high-volume radial corridors 76. But having thus raised readers' expectations I must now proceed to disappoint them. A study, such as the present one (which introduces a concept, produces sample designs, develops performance criteria and conducts a performance evaluation) already has enough on its plate with-out launching into a full-scale cost/benefit analysis or even a detailed and strictly financial cost estimation. Estimates of cost will be made, but they will be merely preliminary and of a comparative nature. Fig.18, p.77, shows the relative cost of various forms of urban 1 freeway construction, based on British data assembled by Lyons. While actual cost values cannot be transferred readily from country to country, indices of relative cost are much less sensitive to differing national conditions (for example: the cost of labour, since labour cost will affect a l l forms, albeit differentially). The index numbers developed by Lyons may for this reason be considered "a useful guide to the rel-2 ativities of different types of road construction". Note that both vertical and sloped open-cuts (termed "depressed: retained" and "depressed open cutting", respectively, in the inset in Fig.18) avoid the extreme cost of a l l tunnel forms. This i s significant because tunnels, particularly the cut-and-cover variety, present a possible alternative way of achieving "null impact" freeways for the bypass function. However, not only would their environment for driving be much poorer, but—according to Lyons' data—their construction cost would be much greater as well. D. J. Lyons. Director-General of Research, [U.K.} Department of the Environment 2 Effects of Traffic and Roads on the Environment in  Urban Areas. Organisation for Economic Co-operation and Development, Paris, 1973, p.50. 77. FIG.18 RELATIVE CONSTRUCTION COST OF URBAN FREEWAYS (excluding land costs etc; after Lyons) Table 1. Relative construction costs of urban motorways (excluding land costs etc.) Form of construction Average index Range of index number number At ground level* . 1 0-7-1-3 Depressed open cutting . 1-5 — Elevated on embankment 2 — Elevated: retained . 3 — Depressed: retained . 5-5 — Elevated: viaduct 7-5 4-10 Tunnel: bored in good conditions . . . . 13 10-16 Tunnel: cut-and-cover . 14 5-30 Tunnel: immersed tube. 25 — Tunnel: bored under 50 18-65 * Cost per lane kilometre at ground level taken as approximately £70 000 at 1969 prices. £0 DEPRESSED-i — i 9> 3 2 g p O cd § P O cd 3 d < a •a T3 0) - P > CO i f p (J S a CD CO ^ •» <o > o O -H s. •H O (0 B o -CD o T— s § g u o £ g -p asO T ) O E e 5 r d o c CO u J 3 3 COCO k (J P U -rl c a> cd (U 03 3 CO CD c w 1—1 co HI C 10 •H >j > U at ns (0 3 o |c o h o O > <i 1 •H . • g a o o •rl •rl J J +iOO 3 andii CO o P U -H andii >- \ r M 4) - P PH ID o (H CO O n CO c a, H TJ o > o o fan o 1 d c! •H 3 i \ •n CO P o i 1 > p o 3 s •d r > •a ••-T P at a> d > d -p CO (4 T 78 The figure also indicates substantial cost advantages of earth-wall cuttings vis a vis the retained variety. And a very favourable cost com-parison between the former and ground-level freeways (an average index number of 1.5 vs 1.0, although the "average" in the case of open cuttings appears to be based on a single example). All of this is highly favourable to the physical design approach presently under investigation. However, our confidence in the present applicability of these latter figures i s somewhat clouded by the fact that Lyons subtitles his Table, "excluding land costs etc." (my emphasis), yet nowhere limits the inclus-iveness of the term "etcetera". Of crucial importance in relation to depressed designs is whether utility relocation costs have been counted in the cost of construction. Presumably they have—it makes l i t t l e sense to exclude them—yet explicit confirmation is lacking. In view of this uncertainty a decision was made to develop indep-endent cost estimates based on a 1971 Vancouver engineering study. (See Appendix I for details). Table 8, p.79, shows two sets of resulting figures: "construction cost per mile" and "construction cost for 3*2 mile route" (i.e. Prior-Venables, the study corridor). All costs are in 1971 dollars and include the cost of 'bridging' local streets and reloc-ating buried util i t i e s . The cost of "at grade" construction, being 1 unknown, was set at a nominal $1.5 million per mile. the Burnaby section of the TransCanada Highway was constructed in the late 1950's and early 1960's at an average cost—exclusive of right-of-way— of $1.5 million per mile. See "The Burnaby Freeway", J. A. C. Andrews, B.C. Professional Engineer, June 1962. TABLE 8; CONSTRUCTION COST ESTIMATES Five Forms of Freeway Construction (Millions of 1971 Dollars) form of construction construction cost per mile construction cost for 3*2 mile route earth slope open cut $7.9 $25.3 retained open cut 14.1 45.1 cut-and-cover tunnel 16.8 53.8 elevated on pier structure 13.9 44.5 i at grade 1«5 4.8 80. While the rank order of construction costs is very similar in Table 8 and Fig .18, the general picture which emerges from the Table is less favourable than before. But this picture changes quickly when we consider "Total Development Cost" (Table 9 , p. 8 1 ) . This is, of course, because any "clear and build" scheme entails very substantial property acquisition costs. In 1971 i t was calculated that in acquiring the over 600 houses of the Prior-Venables alignment an average price per dwelling of $3^,409 would have to be paid. Since that time, the price of real property has escalated, along with the price of labour and material. It seems likely, however, that property cost now forms a more important share of total development cost than was previously the case. (This point will not be pursued further here, but would be worth examining in any subsequent study.) To conclude: (assuming 1971 price relationships): (1) earth-wall open cuts inserted in existing right-of-way appear to have total development costs no greater than at-grade freeways which employ the "clear-and-build" arrangement (2) the total development cost of retained open-cuts in existing right-of-way appears to be significantly less than cut-and-cover tunnels in the same situation; and significantly more than elevated-on-pier-structure even where property must be acquired City of Vancouver East Approach Route Report, Phillips Barratt Hillier Jones and Partners, Vancouver, B.C., 1971. TABLE 9: TOTAL DEVELOPMENT COST of a Freeway in the Prior-Venables Corridor, Various Arrangements and Types (Millions of 1971 Dollars) 'arrangement' type (1) construction cost (2) property cost total development cost,(D+(2) insert sloped open cut 25.3 - 25.3 clear/build at-grade 4.8 20.6 25.4 clear/build elevated on pier structure 13.9 20.6 34.5 insert retained open cut 45.1 - 45.1 insert cut & cover tunnel 53.8 53.8 82. CHAPTER k SUMMARY & CONCLUSION In this final chapter, a synopsis of the study and i t s findings i s presented, and the policy implication of the results explored. 4.1 summary of study and findings The study begins with the contention that opposition to freeway and other urban road construction has grown to such an extent that virtually a l l new development i s blocked. While suggesting that there are valid historical reasons for this opposition, i t i s pointed out that the implied contradiction between the supply of traffic service and the provision of environmental quality i s — f o r a number of measures— demonstrably false. It i s therefore argued that citizen intervention in the process of road planning and development 'on behalf of environmental quality' will likely produce a contrary result: a degraded urban public environment. Traffic—having nowhere else to go—will be forced into the streets. From the points of view of both traffic service and environmental quality the opposite i s desirable: as much traffic as possible should be diverted from surface streets to grade-separated facilities. This i s especially desirable, and practical, in high-volume traffic-degraded corridors. The major difficulty for environmental traffic control by the method just outlined consists in the design of high capacity traffic carriers which do not themselves impose adverse community impacts. Such facilities are termed "null impact" urban arterials. Their attempted design becomes the problem of the remainder of the paper. (scope & method) (l.l] Freeways are defined to be 'null impact' when they substantially avoid the following problems: (i) residential displacement (ii) visual intrusion ( i i i ) noise impact (iv) creation of traffic focal points and •dumping' (v) difficulties of local access and parking (vi) visually poor highway driving environment. The "impact types" to be examined thus form a subset of a l l possible types; the study area i s limited to one-half block on each side of both portions of the facility. For these reasons, the term i s hereafter written 'null impact' (i.e. in single quotes). (l.2] The general study procedure consists of five steps: -development of a "design strategy" and production of sample designs; -selection of two sample designs for application; -conduct of a performance evaluation based on previously-identified impact types; -development of comparitive cost estimates; -drawing conclusions regarding the success or failure of the selected designs. [design & demonstration] £2.13 The design strategy i s to locate the highway within existing right of way, below grade in two separate open cuts; to exclude heavy trucks from using the facility; to keep operating speeds to moderate levels; and to construct the highway without ramps along the length of its route. These provisions are intended to secure needed right of way without residential displacement, to reduce noise impact, and to eliminate the possibility of visual intrusion and 'dumping'. [2.2] Six cross-sectional designs are developed and their respective strengths and weaknesses explored. One each of the two basic types of design (i.e. "vertically retained" and "earth slope" open cuttings) i s selected for application. (2.33 Travel across inner suburbs to and from the downtown is the "urban situation" selected for facility insertion and evaluation. A once-proposed but subsequently abandoned freeway corridor in east end Vancouver is chosen because of i t s history and typicality. [2.4) It i s determined that the test facility would operate at capacity condition in the dominant direction, during peak periods. [performance evaluation) [3.1] All factors except noise are examined in the first part of the Community Impact Analysis: 3^•1• l) "Residential displacement" i s investigated by means of a graphic analysis of the worst case of street misalignment likely to arise. It i s concluded that the test facility i s "null impact" in relation to the "destruction of housing and forced relocation of residents", since, at the very least, i t "substantially avoids" the problem. 3^.1.23 "Visual intrusion": three earlier-specified types of community visual intrusion are discussed in relation to the test designs. After a description of relevant design characteristics, i t i s asserted that no visual intrusion would exist. £3»1 "Traffic focal points and dumping": the elimination of ramps along the route length precludes the possibility of both of these within the study area. In relation to the downtown, i t i s suggested that a restrictive parking policy could be used—selectively and effectively— to avoid traffic oversupply to that area. 85. ^3.1.^ "Local access and parking": the vertically-retained design allows local access and unloading—though not parking—at the property front; the earth-slope design requires a l l functions to be served via rear lanes. A lane pattern is uncovered which would cause denial of both access and parking i f a depressed (earth wall) couplet were constructed, the 'halves' of which were situated one block apart. A T-intersection pattern is developed for use in residential areas where traffic filtering is a pre-existing problem. £3«1 *5~] "Loss of street trees". No matter which of the designs i s employed, complete loss of existing street trees i s unavoidable. Where loss of trees is seen to be a problem, replacement trees can be installed on private property at public expense. Where existing trees are small, substitution can be satisfactory and complete. £3.2] The Environment for Driving: Several means of improving the aesthetic quality of environments completely enclosed by concrete retain-ing walls are discussed. It i s concluded that "at least acceptable" environments for driving can be designed in vertical cuts. In respect of the earth slope form, a graphic analysis i s conducted to determine the extent—and content—of the unconstrained cone of vision available to a driver in the cut. It appears that his field of vision would not be unduly constricted by the cut. When furnished with large-scale plant material, the driving experience through the open cutting may well be a pleasant one. [3.3] Noise Impact Analysis f3»3«l3 •riie matter of a suitable "criterion of impact" is canvassed extensively. Eventually 65 dBA at the level is selected as the most suitable single value. The selection is justified on a number of grounds —perhaps the most important of which i s that outdoor traffic noise of 86. this level permits outdoor speech to be conducted in a normal voice at distances of two to five feet. The standard would thus allow two persons to carry on a normal conversation while walking side by side in the open air. £3.3.2] The impact criterion i s further developed by defining degrees of noise impact. The threshold of impact i s defined to be a zone centering on 65 dBA and extending some distance above and below i t . In the end, five degrees of impact are distinguished: "no", "marginal", "definite", "serious" and "severe" impact. simulation model i s selected for use. (The simplified form is accurate to within 2 decibels of the answer obtained by the more detailed method; the computer model itself produces figures virtually indistinguishable from those read directly from the noise meter.) Some difficulties are encountered in applying the method. To circumvent these, a 'first run' simulation i s made assuming no reductive effect due to the highway's depressed location. In this way the worst possible noise exposure at two positions relative to the highway i s established. Next, a detailed analysis is made to determine the amount of noise reduction to be reasonably expected at the sidewalk due to highway config-uration. Two values (a maximum and minimum) are chosen for the sidewalk position. At the building facade/ determination of shielding effect and exposure i s not problematic. It is concluded that the vertical design will have a marginal to definite impact at the sidewalk, depending on actual shielding effective-ness. L^Q exposure at the building facade will be at or below the impact threshold. A simplified analytical form of a computer 87. The sloped design will produce a definite, though not serious, sidewalk impact. L^Q exposure at the building facade will f a l l entirely within the impact threshold. Finally, combined exposure (from two highway sources operating simultaneously, at various conditions of speed and flow) i s calculated. It i s found that in no case would combined exposure exceed exposure from the nearby facility alone. [3«4J Financial Cost.' While pointing out that the crucial question in relation to cost is not so much total amount but rather whether total benefits exceed total costs, i t i s admitted that a f u l l scale cost/benefit analysis i s beyond the study's scope. Instead, preliminary comparative cost estimates are developed and presented. Data from a British source indicate that each of the open cut forms of construction avoid the extreme cost of a l l tunnel forms. Estim-ates derived from a Vancouver engineering study point to the same conclusion but less decisively. In terms of total development cost (aamore significant figure than simple construction cost) the earth slope form is at about the level of at-grade construction in an inner city "clear and build" scheme. The cost of the retained open cut is about 80# greater. 88. 4.2 conclusion Regarding the success or failure of the selected designs, i t appears justified to conclude that one of them—the vertical cutting— avoids to a very considerable extent a l l important negative effects in the impact areas chosen for examination. But to avoid any possible controversy or misinterpretation which might be occasioned by use even of the restricted term 'null impact* in relation to this designj.s performance, i t appears desirable to settle for a somewhat weaker claim. It i s therefore concluded, only, that the technical feasibility of a minimal community impact urban freeway has been demonstrated. 4.3 policy implication In terms of policy, what i s the importance of the conclusion just stated? In i t s most simple form i t i s that i f the environmental advantages of off-street, continuous-flow operation of motor vehicles are in fact to be gained, freeways must be provided for vehicular use. If freeways can be provided without serious community disruption, then overall improvement i s likely by this method. One writer on the subject of traffic/environent conflicts in fact proposes^aa a criterion of the quality of the urban environment^ the extent to which traffic i s diverted from surface streets to grade-1 separated facilities. By "grade-separated facilities" is meant Hans Blumenfeld, "Criteria for Judging the Quality of the Urban Environment" in H.J. Schmandt and W. Bloomberg, Jr. (eds.) Urban Affairs Annual Reviews, Volume 3 (1969), Sage Publications, Inc., Beverly Hills, Calif. 89 "subways for transit, and especially freeways for cars and trucks, as well as buses". One need only accept the proposition that traffic in the streets interferes with a good living environment to adopt this as a criterion of environmental quality. A second aspect of this work's possible implication for policy concerns the most advantageous balance between transit and road invest-ment in urban areas. Apparently, transit investment is often proposed in the belief that i t can reduce (or at least contain) motor vehicle movements and their harmful impacts. Some authorities have called this 2 a myth. If the objectives of transport investment are in any important degree environmental, then alternative investments must be justified on environmental grounds. This study raises the possibility that an appropriately designed freeway may be more effective as an environmental measure than a new transit facility. A detailed cost-effectiveness study i s warranted to determine this point. 1 i b i d 2 B.G. Hutchinson, "Some Urban Transportation Myths", a paper presented to the Annual Convention of the Roads and Transportation Association of Canada, Winnipeg, October 1972; with Commentary by Hans Blumenfeld. Reprinted in University of Waterloo Occasional  Paper series. r LITERATURE CITED American Association of State Highway Officials. Policy on Design  of Urban Highways and Arterial Streets. 1973. Washington D.C., 1974 Andrews, J.A.C. "The Burnaby Freeway", B.C. Professional Engineer June 1962 Barron and Strachan, Consulting Acoustical Engineers. A Community  Noise Survey of the Greater Vancouver Regional District. Vancouver B.C., 1971 Beranek, Leo L. "Noise", Scientific American, vol.215, no.6 (Dec. 1966) Blumenfeld, Hans. "Criteria for Judging the Quality of the Urban Environment" in H.J. Schmandt and W. Bloomberg, Jr. (eds.) Urban Affairs Annual Reviews. Volume 3 (1969), Sage Publi-cations, Inc., Beverly Hills, Calif. Citizens Policy Committee for Transportation and Transmission (of the Greater Vancouver Regional District). Report On Trans- portation For A Livable Region, submitted to the Board of the Greater Vancouver Regional District, October 1973 Creighton, Roger L. Urban Transportation Planning. University of Illinois Press, Urbana 1970 Fried, Marc. "Grieving for a Lost Home" in L.J. Duhl (ed.) The  Urban Condition: People and Policy in the Metropolis. Basic Books, 1963 Galloway, W.J., W.E. Clark, and J.S. Kerrick (of Bolt, Beranek and Newman Inc., Van Nuys, Calif.). Highway Noise: Measurement. Simulation, and Mixed Reactions, National Cooperative Highway Research Program Report 78, Highway Research Board, 1969 Highway Research Board. Committee on Highway Capacity. Highway  Capacity Manual. Washington D.C., 1965 Hutchinson, B.G. "Some Urban Transportation Myths", a paper presented at the Annual Convention of the Roads and Trans-portation Association of Canada, Winnipeg, October 1972; with Commentary by Hans Blumenfeld. Reprinted in University of Waterloo Occasional Papers series Lynch, Kevin. Site Planning. MIT Press, 1962 Lyons, D.J. "Trends in research in motorway design and use" in Motorways in Britain today and tomorrow. Institution of Civil Engineers, London 1971 Organisation for Economic Cooperation and Development. Effects  of Traffic and Roads on the Environment in Urban Areas. OECD, Paris, 1973 Research into Road Safety at Junction in Urban Areas, OECD, Paris, 1971 Phillips Barratt Hillier Jones & Partners. City of Vancouver  East Approach Route Report, Vancouver B.C., 1971 Ross, Sir David (trans). The Nicomachean Ethics of Aristotle, Oxford University Press, London, 1971 (reprint) Sherwood, P.T. and P.H. Bowers. Air Pollution from Road Traffic  — a review of the present position, [UKJ Road Research Laboratory Report LR 352, 1970 Swan Wooster - CBA Engineering. Notes on the Burrard Inlet Cross- ing Approaches — C i t y of Vancouver; Examination of Alterna- tive Concepts. Swan Wooster - CBA Engineering, Vancouver B.C. October 1968 Urban Advisors to the Cus) Federal Highway Administrator. The  Freeway In The Cityt principles of planning and design, United States Government Printing Office, Washington D.C., 1970 APPENDIX I METHOD AND DATA USED TO DERIVE CONSTRUCTION COST ESTIMATES All costs are in 1971 dollars. They are derived from itemized cost estimates in City of Vancouver East Approach Route Report (Phillips Barratt Hillier Jones and Partners, Consulting Engineers and Architects, Vancouver BC, August 1971) pp.134-143. method; Since what is wanted are estimates of general applicability, the following procedure has been applied to estimates contained in the consultant's report: (1) a l l factors peculiar to a specific situation have been excluded from consideration (e.g. railway relocation costs); (2) a l l project cost estimates have been 'normalized' in the sense that they have been put on a cost per mile basis, to enable comparison. In practice this has meant consistently including the cost of the following items: excavation, f i l l and finish grading; gravel base course, asphalt pavement, curbs and drains; retaining walls; and 15% engineering and contingency costs. The cost of 'bridging' local streets across open cuts has been put at $250,000 per bridging. This i s about the cost of construction of the Main St. ramps in Schemes i l l and Vi5i $225,300 and $239,800 resp-ectively. (One-quarter of a million dollars may be an inflated amount for a maximum of 122 feet of bridging per crossover, but a negative bias in the figures is to be preferred to a positive one. For the same reason, an extra $2 million per mile has been added to the cost of each of the below-grade forms to allow for the relocation of ut i l i t i e s . (It is felt that the types and amounts of "utility disruption" included in the source estimates do not adequately reflect the costs to be incurred in the study situation; i.e. they are far too low.) earth-slope open cut Estimate based on cost items A C D of Scheme 6 . 0 . The sum of these items divided by 2 (the "scheme" accounts for 10,600 feet of highway) is $3.75 million. $ 3.750 million . . . . . . . basic items, adjusted 1.125 " . bridging: $ 1/4 million per crossover times an average of 4.5 crossovers per mile 2.000 • " utility relocation 6.875 " + 15% . engineering & contingency $ 7.9 million per mile construction cost retained open cut Estimate based on Scheme 8.2, . cost items A C D, adjusted to reflect the cost of a retained open cut of average depth: 14 feet. To accomplish this adjustment, items A and D are increased in value by k0% (the cut varies in depth from zero to 20 feet, for an average depth of 10 feet). A second adjustment is required because the "cut" portion accounts for only 1/3 of the route length of Scheme 8 . 2 ; consequently, the value of cost item "C" has been reduced by 2/3. 'Normalization*: since the cut is only 1750 feet long, the results of the upward adjustment of A and D and the downward adjustment of C must—when added together—be tripled. 94. $9.14 million items A C D of 8 . 2 , adjusted 1.125 " bridging 2.000 " utility relocation 12.265 million +15% engineering & contingency $14.1 million per mile construction cost cut and cover tunnel Tunnel costs of Schemes 1.5, 4 . 0 and 8.2 were examined. The respective length of these tunnels i s .23, .43 and .15 miles. In the case of the first two, the cost of the tunnel includes lighting, ventilation, and ti l e lining, although—apparently—not the cost of road surfacing; in the case of the third, "lighting, t i l e lining and pumping station" are counted in the cost. Per mile cost of these tunnels in 12.5, 11.9 and 19.3 million dollars, respectively. The extremity of the latter cost i s presumably due to the inclusion of a pumping station in the design. Since this is an extra-ordinary cost, Scheme 8.2 will not be considered further. If 1/3 of the cost of cut, f i l l and finish grading, and gravel base course, pavement, curbs and drains (Scheme 1.5) is added to the average cost of cut and cover tunnels without pumping stations, the resulting cost-per-mile of tunnel plus roadway is $ 12.6 million. Other costs raise the amount to $ 16.8 million. $ 12.598 million cost of tunnel plus roadway 2.000 " utility relocation 14.598 million + 15# engineering & contingency $ 16.8 million per mile construction cost elevated on pier structure Estimate based on Scheme 3 . 0 , cost items A C D E F. With 15# contingency and engineering, the construction cost amount for this 1.2 mile route i s $ 16.6543 million. Normalized, the cost become6H3«9 million, APPENDIX II Calculation of Theoretical Noise Exposure at Two Points Assuming No Shielding Effect Since the simulation model yields (or median noise level) upward adjustment i s necessary to obtain a figure representing the highest decibel level exceeded only 10# of the time (the L^'level). For this purpose/the noise simulation report provides Fig.6: "Curves for estimation of the standard deviation of noise levels in dBA..." Assuming a normal distribution about the mean, 1.29 standard deviations to either side of the mean describes an area containing 80.3# of the total; when the t a i l end of the distribution to the left i s added in, 90.15$ of the area under the curve i s accounted for. Thus, 1.29 times the standard deviation in decibels, when added to the mean noise level, yeilds that level (^Q) exceeded not more than 10% Of the time. It should be noted that as vehicle density per mile of roadway increases, i.e. as the traffic flow becomes more continuous (less intermittent), the distribution of noise levels about the mean becomes progressively more peaked; and dBA values per standard deviation show a consequent decrease. Vehicle densities per mile for the four traffic flow situations are as follows:. #1 (120/mi), #2 (80/mi), #3a (50/mi), #3b (45/mi), #4a (22/mi), #kb (21/mi); their respective dBA values for one standard deviation are 1.25, 1»5» 1*8, 1.9, 2.5, 2.5 decibels. For purposes of breaking down each estimate into i t s constituent parts, each expression in the formula for average noise level i s assigned a letter from "a" to "d", as shown below: L s ICO^ og^ Qq - 10 log 1 0d + 20 log 1 0 y + 20^  ( L ^ level) "a" - "b" + "c" + "d" 96. Situation #1t at sidewalk "a"...+36.021 "b"...-14.771 M...+30.212 "d"...+20.000 L 5 0 = 71.462 L 1 0 = 73.075 at blag, facade "a H... +36.021 "b"... -17.386 "c"... +30.212 "d"... +20.000 u50 So 68.847 70.460 Situation #2: at sidewalk "a"...+34.771 nb'»...-l4.771 "c"...+32.042 "d"...+20.000 L^ 0 = 72.042 L 1 0 = 73.977 at bldg. facade "a"... +34.771 "b"... -17.386 "c"... +32.042 u50 ho 69.427 71.362 Situation #3* 3(a): 3(b): at sidewalk "a"...+33.010 •V1...-14.771 V 1... +32.042 "d"...+20.000 L50 = L10 = 'L50 = LLio = 70.281I 72.603 71.303 73.754 at bldg. facade "a"... +33.010 •v... -17.386 "c"... +32.042 "d"... +20.000 L50 = ^10 = "50 -L10 = 67.666 69.988 68.688" 71.139 Situation #4: 4(a): 4(b): at sidewalk "a"...+30.000 "b"...-14.771 "cM...+32.042 "d"...+20.000 L50 = L10 = "L50 = L10 = 67.271 70.496 68.293 71.518 at blgd. facade "a"... +30.000 -17.386 "c M... +32.042 "dM... +20.000 "50 L L io J50 So 64.656 67.881 65.678" 68.903 97 APPENDIX III THE STUDY AREA IN DETAIL The appended Sheets, 1-11, form a continuous map of the study route. The extent of the study area is shown in yellow colour (the number and position of buildings within i t are clearly visible, as are the width and pattern of existing rear lanes). Red circles identify the four points along the route at which street-segments are not perfectly aligned. (Sheets 3t 6, 8, 10). Oneof these (Sheet 3) does not involve residential buildings. Another (Sheet 6) is minor. That in Sheet 8 involves sufficient unoccupied land that connection can easily be made. Only the remaining offset—Venables at Windermere, visible in Sheet 1 0 — i s the type which could potentially cause displacement. ' 9 6 2 i 2 . 6 0 ' : AvE. > 2. H O CO 3 m o o ro o -* U - v A -___m. 01 o o V. to ro IVJ CA f ^ B E L 7 6 0 0 L AvE F L a Q j a PES QBlj CO 01 1 9 8 / 5 9 8 PRINCESS AVE. - a c d tZZJi i 1 i ^ — i 1 m J - L—1 • i i i—i _ Q j i r — r • •} 1 & ID co ID 0 0 O CO 2 0 5 / 5 9 8 H E A T L E Y AVE. n n n • - 7 — ^ — • — * ~r—n 1 1 a n ' r —1 •ii—' [ 1 i • j r — 1 1 en CD \ ro o 2 1 2 / 5 9 8 HAWKS AVE. TJ _^ CZZ1 J = 3 "C=J CD • • is a-. 198/596 198/594 D a m o CD. ro 2 1 7 / 5 9 8 C A M P B E L L AVE. I y a — a B •nan 01 CO a m o JO Q 1> CO e g 1— i a Or ! • 205/596 CD C3 I 212/596 • • 0 1 2 1 7 / 5 9 6 r n E05/594 01 to -01 \ ro O cr "0 0 > r m > z: 2 1 2 / 5 9 4 [ana to ro ro c c I •66 1 E T 10 CVJ S C H O O L CM 1 1 T O L E B B • o ro CVJ ADANAC ST fr •a rr co Q en I D \ o ro CM ^ < _i VENABLES •0 <\l rg 601 / 2 28 PARKER ST or 5 o 8 CLARK 101 102. L T D 5 r~ 965/53? -TR1 • n Q DDD'D • a • C J I I jJBL : • F E B 965/252 CO o O UJ a m 10 tn in a EE • EL n a • JZL 965/152 • a E H OB o m IX) en i n F=5 • a • a in : B : z o o U3 865/552 ro i n cn i n IS E 1 3 o o i n in O U3 ya N I0S P a ro m C\J I O r 10 865/252 Q09/2S2 109/ in n • o " a s ET 009/252 109/ E r a ya Ayngsnvs 865/152 CO H o o • PLTB o i n I\J \ o ID 4* 009/052 109/ o o to i t La a • 5 9 6 / ^ 5 GEORGIA 5T ID TEMPLETON PARKzi 10 •Jl — O r -5 9 8 / 2 5 5 5 9 8 / L ' t 9 Vt8/?<, A D A N A C ST L4M/J(.< 3 * r r 1 1 1 1 1 1 1 1 1 1 6 0 0 / 2 5 5 a) C O T 600/259 E : -~ . — 1 1 : i 1 C o o —1 1 U) Li-b 1 1 M i 1 i i s i f 1 I -s cn in 4-1 TO fiOO/265 VENABLES ST r i 4 i | i 601/255 601/259 601/265 PARKER ST 601/267 0 irtiWttmj rtrtorira] m m o ID 2 70/601 270/COO 274/601 • & 1 275/601 II I I trr 271/600 en o ro si 274/600 CD. O ro 275/600 2 70/598 270/596 NAN AIM 0 ST 3 i 271/ 598 271 /596 KAMLOOPS ST. LP ID CO r> 274/598 O o \ IM 274/596 PENTICTON ST. ?70 ug cn rv o 271 10 2 7 2 75/598 275/5'je SLOCAN ST f^Fffl FRTO FFHFRI rnnrcf 'tfOL 5/601 275/ sye SLOGAN ST. 275/544 en I O - 2 U o r-00 280/596 RENFREW ST. T Z D r r m _ng i s 3 a 277/594 CO EEFI i CD Z j • _ c - I — 1 ,0b) •£oi 280/600 280/598 282/600 01 o o ro 03 rjU ' 1—LI , 1 1 1 1 , 1 , l LT - ft • • d . • _ • IB z 282/598 1 1 i 1 1 1 1 1 - f l ' : l - H H -289/G00 289/5^8 •1 J I M ! 0 - EST qrjnDnmd] M M o 280/596 RENFREW ST. 28C/594 i n 282/596 N00TKA ST. = 0 ~ u -Pi D . a rh Q • T T " a n = r ~ n a • 289/596 LILL00ET ST. 282/594 U3 28y/5a4 10 " 9 0 L 'LOl a-: _c£L tft • • 298/6U0 298/598 to I T 03 if GO N o o 298/596 RUPERT ST. Ul • a t o a fl ro CO 300/596 CASSIAR ST. E E • ran Bco±fc0 3 0 5 / 5 9 G SKEENA ST. Ul I D 29f S a 3C 3 0 ! I J I I • 

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