Applied Science, Faculty of
Engineering, School of (Okanagan)
DSpace
UBCO
Juniper, Scott Heath
Master of Applied Science - MASc
University of British Columbia
As relatively novel intersections, roundabouts have garnered support and interest from many countries due to traffic flow and safety improvements over traditional intersections. Despite growing application, knowledge and experience is relatively scarce within Canada for multilane roundabouts (MLR’s); the Canadian Roundabout Design Guide was only published in 2017 and was largely based on US guidance. Turbo Roundabouts are an emerging multi lane roundabout design successfully implemented in Europe over the past 20 years, however nowhere yet applied in Canada, and rarely in the United States. Claimed to reduce safety risk for all users (not just automobile), decrease greenhouse gas emissions, increase climate resiliency, and reduce lifecycle costs for an intersection, Turbo Roundabouts present a MLR design option that warrants consideration for Canada; there is also considerable opportunity to implement this design due to increased capacity over a single lane roundabout. Many research teams have demonstrated injury risk being significantly lower to auto and non-auto road users by implementing this design. This lower risk is due to several design features, including spiral circulating lanes, physical lane dividers, and adequate separation for pedestrian and bicyclist crossings – among others. This research determined Turbo Roundabouts are applicable to Canada, have significant potential social, environmental, travel time, and safety benefits, however knowledge gaps exist to accommodate design. Research methods included literature review of existing MLR design, a case study feasibility design project, and field visits to existing Turbo Roundabouts in Europe. Findings of the research were that Turbo Roundabouts cannot be applied in Canada without a few adjustments; particularly, lane divider width, circulating radii, and entry radii would need modification for the longer design vehicles in Canada. Snow removal equipment was not found to be a barrier to Turbo Roundabout implementation, contrary to common perception. An innovative intersection like Turbo Roundabouts would likely require driver education as well. Existing Canadian design guidelines have yet to provide guidance for Turbo roundabouts, and no planning level tools exist pertaining to Canadian specific requirements. There are currently two roundabouts constructed in Canada that aspire to some aspects of turbo roundabout design features, despite hundreds constructed in Europe.
SUSTAINABLE TRANSPORT SAFETY: ARE TURBO ROUNDABOUTS APPLICABLE TO CANADA? by Scott Heath Juniper B.A.Sc. The University of British Columbia, 2020 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE COLLEGE OF GRADUATE STUDIES (Civil Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) July 2024 © Scott Heath Juniper, 2024 ii The following individuals certify that they have read, and recommend to the College of Graduate Studies for acceptance, a thesis entitled: ARE TURBO ROUNDABOUTS APPLICABLE TO CANADA? submitted by Scott Heath Juniper in partial fulfillment of the requirements for the degree of Master of Applied Science in Civil Engineering Examining Committee: Dr. Gordon Lovegrove, School of Engineering Supervisor Dr. Mahmudur Fatmi, School of Engineering Supervisory Committee Member Dr. Peter G. Furth, Northeastern University Supervisory Committee Member Dr. Yves Lucet – Irving K. Barber Faculty of Science University Examiner iii Abstract As relatively novel intersections, roundabouts have garnered support and interest from many countries due to traffic flow and safety improvements over traditional intersections. Despite growing application, knowledge and experience is relatively scarce within Canada for multilane roundabouts (MLR’s); the Canadian Roundabout Design Guide was only published in 2017 and was largely based on US guidance. Turbo Roundabouts are an emerging multi lane roundabout design successfully implemented in Europe over the past 20 years, however nowhere yet applied in Canada, and rarely in the United States. Claimed to reduce safety risk for all users (not just automobile), decrease greenhouse gas emissions, increase climate resiliency, and reduce lifecycle costs for an intersection, Turbo Roundabouts present a MLR design option that warrants consideration for Canada; there is also considerable opportunity to implement this design due to increased capacity over a single lane roundabout. Many research teams have demonstrated injury risk being significantly lower to auto and non-auto road users by implementing this design. This lower risk is due to several design features, including spiral circulating lanes, physical lane dividers, and adequate separation for pedestrian and bicyclist crossings – among others. This research determined Turbo Roundabouts are applicable to Canada, have significant potential social, environmental, travel time, and safety benefits, however knowledge gaps exist to accommodate design. Research methods included literature review of existing MLR design, a case study feasibility design project, and field visits to iv existing Turbo Roundabouts in Europe. Findings of the research were that Turbo Roundabouts cannot be applied in Canada without a few adjustments; particularly, lane divider width, circulating radii, and entry radii would need modification for the longer design vehicles in Canada. Snow removal equipment was not found to be a barrier to Turbo Roundabout implementation, contrary to common perception. An innovative intersection like Turbo Roundabouts would likely require driver education as well. Existing Canadian design guidelines have yet to provide guidance for Turbo Roundabouts, and no planning level tools exist pertaining to Canadian specific requirements. There are currently two roundabouts constructed in Canada that aspire to some aspects of Turbo Roundabout design features, despite hundreds constructed in Europe. v Lay Summary Turbo Roundabouts are a new modern roundabout design being implemented in foreign countries proving successful at increasing safety, capacity, and functionality for all users (not just automobile). This research reviewed multilane roundabout design literature, investigated potential lifecycle cost benefits of application of Turbo Roundabouts, field verified traffic volumes these intersections serve, determined that Turbo Roundabouts are a valuable intersection design choice for Canada, and discovered how Turbo Roundabouts may need to be adjusted from European design methods to accommodate North American requirements in the future. vi Preface Chapters 1 and 2 contain components of a conference paper that accompanied my presentation at the 2021 Canadian Society for Civil Engineering’s annual conference. The Title of the conference paper was “A REVIEW OF THE LITERATURE ON DESIGN AND PERFORMANCE OF MULTI LANE ROUNDABOUTS IN CANADA: THE CASE FOR TURBO ROUNDABOUTS”. I performed the literature review and wrote most of the paper, with revisions and guidance by Dr. Lovegrove. No generative AI was used in preparation of this thesis, or for any aspect of the work involved. vii Table of Contents Abstract ......................................................................................................................... iii Lay Summary ................................................................................................................. v Preface .......................................................................................................................... vi Table of Contents ........................................................................................................ vii List of Tables ............................................................................................................... xii List of Figures ............................................................................................................ xiii List of Abbreviations ................................................................................................... xv Glossary ...................................................................................................................... xvi Acknowledgements .................................................................................................. xviii Dedication ................................................................................................................... xix Chapter 1: Introduction ................................................................................................. 1 1.1 Research Objectives and Gaps ........................................................................ 2 1.2 Turbo Roundabouts – What Are They? ............................................................ 3 1.3 Turbo Roundabouts – Why Do They Exist? ...................................................... 4 1.4 Thesis Format and Structure ............................................................................. 5 Chapter 2: The Case for Turbo Roundabouts and Literature Review ....................... 7 2.1 Spiral Lane Geometry ....................................................................................... 8 2.2 Physical Lane Dividers .................................................................................... 10 2.3 Approach Lane Vectors .................................................................................. 14 2.4 Pedestrian and Cyclist Crossings ................................................................... 15 2.5 Placement within Network and Capacity ......................................................... 16 viii 2.6 Canadian Roundabout Design Guide (2017) .................................................. 17 2.7 Dutch Design Manuals .................................................................................... 18 2.7.1 Roundabouts – Application and Design (2009) ........................................ 18 2.7.2 Turbo Roundabout Design Manual – CROW Publication 257 (2020) ...... 19 2.8 Chapter Summary ........................................................................................... 21 Chapter 3: Kelowna Case Study - Feasibility Design Project in Local Context ..... 23 3.1 Site Background .............................................................................................. 23 3.2 Methodology ................................................................................................... 27 3.3 Data Collection ................................................................................................ 28 3.4 Feasible Option Analysis................................................................................. 29 3.4.1 Rotor Style Turbo Roundabout ................................................................ 30 3.4.2 Low Angle Slip Lanes vs. High Angle Slip Lanes ..................................... 31 3.4.3 Signalization (Metering) ........................................................................... 34 3.4.4 Analysis Findings ..................................................................................... 35 3.5 Conceptual Design Alternatives ...................................................................... 36 3.5.1 Option 1: Do Nothing ............................................................................... 36 3.5.2 Option 2: Turbo Roundabout ................................................................... 36 3.5.2.1 Option 2.1 MUP Underpass ................................................................. 36 3.5.2.2 Option 2.2 MUP Overpass ................................................................... 37 3.6 Design Selection ............................................................................................. 38 3.7 Preliminary Geometric Design ........................................................................ 40 3.7.1 Minimum Radius and Lane Width ............................................................ 41 3.7.2 Over Tracking Lanes................................................................................ 45 ix 3.7.3 Constrained Use Lanes ........................................................................... 46 3.7.4 Fastest Path Analysis and Expected Speed ............................................ 46 3.7.5 Notes to Application on Smaller Intersections .......................................... 47 3.8 Economic Analysis .......................................................................................... 48 3.8.1 Safety Benefits ......................................................................................... 48 3.8.2 Travel Time, and Environmental Benefits ................................................ 51 3.8.3 Capital Cost Estimate .............................................................................. 54 3.9 Chapter Conclusion ........................................................................................ 55 Chapter 4: Europe Field Visits – Dutch Case Study ................................................. 57 4.1 Background ..................................................................................................... 58 4.1.1 Origin of the Road Network and Topographic Context ............................ 58 4.1.2 Political Context Shaping Road Policy Changes ...................................... 60 4.1.2.1 Sustainable Safety – The Dutch Model ................................................ 60 4.1.2.2 Vision Zero – The Swedish Model ........................................................ 62 4.1.2.3 Canadian Road Safety Strategy 2015 (2011) ....................................... 62 4.1.2.4 CROW Dutch Resource Library Vs TAC Canadian Resource Library . 63 4.1.2.5 Division of Roads Ownership between Governments .......................... 64 4.1.2.6 Education and Licensing Differences ................................................... 64 4.1.3 Environmental Context............................................................................. 68 4.1.3.1 Weather ................................................................................................ 68 4.1.4 Technological Context ............................................................................. 71 4.1.4.1 South Holland Highways Group of the 1990’s and Early 2000’s .......... 71 4.1.4.1.1 Turbo Roundabout Definition ......................................................... 72 x 4.1.4.2 Turbo Roundabouts Constructed to Date ............................................. 73 4.2 Methodology ................................................................................................... 74 4.2.1 Sites Visited ............................................................................................. 75 4.2.2 Province of South Holland Traffic Counts ................................................ 76 4.2.3 In Person Traffic Counts & Velocity Measure .......................................... 76 4.3 Location Data .................................................................................................. 77 4.3.1 Location 1 ................................................................................................ 77 4.3.2 Location 2 ................................................................................................ 78 4.3.3 Location 3 ................................................................................................ 79 4.3.4 Location 4 ................................................................................................ 80 4.3.5 Location 5 ................................................................................................ 81 4.3.6 Location 6 ................................................................................................ 82 4.3.7 Location 7 ................................................................................................ 83 4.3.8 Location 8 ................................................................................................ 84 4.3.9 Provincial Comparison Data .................................................................... 85 4.4 Chapter Conclusion ........................................................................................ 87 Chapter 5: Discussion ................................................................................................ 88 5.1 Upstream versus Downstream Control ........................................................... 88 5.2 Safety Principles ............................................................................................. 88 5.3 Stewardship, the role of Government, and Safety ........................................... 92 5.4 Intelligent Vehicles .......................................................................................... 93 5.5 Ethical Quandaries .......................................................................................... 93 Chapter 6: Conclusions .............................................................................................. 95 xi 6.1 Kelowna Case Study Conclusions .................................................................. 95 6.2 Europe Field Visits Conclusions ...................................................................... 96 6.3 North America Trends ..................................................................................... 97 6.4 Contributions of the Thesis ............................................................................. 98 6.5 Lessons Learned and Future Research Opportunities .................................... 99 Bibliography .............................................................................................................. 104 Appendices ................................................................................................................ 113 Appendix A Sidra Turbo Roundabout Parameters ................................................... 113 Appendix B WB-21 Information ............................................................................... 114 Appendix C Sidra Reports for Feasibility Design ..................................................... 117 Appendix D Preliminary Case Study Design Drawings ............................................ 129 Appendix E Preliminary Case Study Construction Cost Estimate ............................ 144 Appendix F Preliminary Case Study Capital Cost Estimate ..................................... 150 xii List of Tables Table 1 - Key Differences between Modern Roundabouts and Turbo Roundabouts .... 22 Table 2 - Rotor Roundabout Dimensions [3] ................................................................. 47 Table 3 - KABCO Injury Level Classification Table ....................................................... 49 Table 4 - Relationships of Severity Indexes and Injury Levels ...................................... 49 Table 5 - Collision Data of Benvoulin, Dilworth, and Springfield Intersection ................ 50 Table 6 - Anticipated Yearly Collision Cost Benefits ..................................................... 50 Table 7 - Stratified Distribution of Daily Traffic .............................................................. 53 Table 8 - Travel Time Cost & Emissions - Existing vs Proposed ................................... 54 Table 9 – Annual Costs and Benefits Summary ............................................................ 56 Table 10 - Field Visits by Roundabout Type .................................................................. 75 Table 11 - Provincial Data Comparison Table ............................................................... 86 Table 12 - Engineering 'Feature Effects' Observed within Modern Roundabout Geometry [1] ................................................................................................................. 89 xiii List of Figures Figure 1 - Standard Layout of Basic Turbo Roundabout [6] ............................................ 4 Figure 2 - Collision Frequencies at US Intersections Converted to Roundabouts ........... 5 Figure 3 - Turbo Block Detail ........................................................................................... 9 Figure 4 - Comparison of Multi Lane and Turbo Roundabout Conflict Points, Adapted From [5] ......................................................................................................................... 10 Figure 5 - Turbo Roundabout Frogs .............................................................................. 11 Figure 6 - Physical Lane Dividers, Adapted From [3] .................................................... 12 Figure 7 - Collisions Type Comparisons Between Turbo Roundabouts With and Without Raised Dividers, Adapted From [13].............................................................................. 13 Figure 8 - Approach Axis Line [3] .................................................................................. 15 Figure 9 - Fastest Path Performance Check Comparison [1], [9] .................................. 21 Figure 10 - Google Earth Photo of Benvoulin (South), Springfield (East & West), and Dilworth (North) Intersection .......................................................................................... 24 Figure 11 - Kelowna Urban Centres [25] ....................................................................... 26 Figure 12 - XS-R87 Core Area Major Arterial - CoK Class 1 Parkway [27] ................... 27 Figure 13 - Peak Flow Turning Movements, Weekday PM [28] .................................... 29 Figure 14 - Dutch Rotor Style Turbo Roundabout [21], Used with Permission .............. 31 Figure 15 - High Angle Slip Lane, Adapted From [34] ................................................... 32 Figure 16 - Level of Service (A thru E) Achievable on Rotor Style Turbo Roundabout with Low Angle Slip Lanes and Signalization ................................................................ 33 Figure 17 - LoS Achievable on Rotor Style Turbo Roundabout with Signalization ........ 34 xiv Figure 18 - LOS Findings of Tested Intersection Options.............................................. 35 Figure 19 - City Park Tunnel, Kelowna .......................................................................... 37 Figure 20 - AHP Determination for Transportation Priorities Within The City of Kelowna ...................................................................................................................................... 39 Figure 21 - Multiple Account Evaluation (MAE) of the Conceptual Design Alternatives Using AHP ..................................................................................................................... 39 Figure 22 - Turbo Roundabout Sketch with MUP Tunnels ............................................ 41 Figure 23 - Fastest Vehicle Path through Multi lane Roundabout ................................. 42 Figure 24 - Canadian WB-21 Profile Dimensions [37], Used with Permission ............... 43 Figure 25 - Canadian WB-21 Plan Dimensions [37], Used with Permission .................. 43 Figure 26 - Canadian WB-21 Turning Profile [37], Used with Permission ..................... 43 Figure 27 - Dimensioning Vehicle for European Roadway Roundabouts [21], Used with Permission .................................................................................................................... 44 Figure 28 - Turbo Block Layout for Rotor Roundabout .................................................. 48 Figure 29 - Weekday and Weekend Traffic Distribution Profiles, Adapted From [44] .... 52 Figure 30 - Temperature and Precipitation Graph, with Data From The World Meteorological Association for Utrecht, [58] .................................................................. 69 Figure 31 - Temperature and Snowfall Graph [59] ........................................................ 70 Figure 32 - Basic Turbo Roundabout ............................................................................ 73 Figure 33 - Turbo Roundabouts Constructed within Europe to Date, Adapted From [60] ...................................................................................................................................... 74 Figure 34 - Map of Sites Visited Within the Netherlands ............................................... 75 xv List of Abbreviations NAMLR – North American Multilane Roundabout MLR –Multilane Roundabout TR – Turbo Roundabout SLR – Single Lane Roundabout TAC – Transportation Association of Canada NCHRP – National Cooperative Highway Research Program CoK – City of Kelowna TMP – Transportation Master Plan DCC – Development Cost Charge OCP – Official Community Plan ICBC – Insurance Corporation of British Columbia AADT – Annual Average Daily Traffic CCMTA – Canadian Council of Motor Transport Administrators EU – European Union xvi Glossary Central Island – A raised area in the middle of the roundabout, where the roadway passes around. The central island is not necessarily circular, and is potentially passable if constructed within a Mini Roundabout Circulatory Roadway – The circulatory Roadway is the road used by automobiles travelling around the central island Entrance Line – The entrance is a painted dashed line marking the point of entry to the circulatory roadway; this line may contain other markings to designate yielding for incoming traffic Inscribed Circle Diameter (ICD) – The ICD is a design element that influences capacity, speed, and safety of a particular roundabout; the ICD is the largest circle diameter that may fit within an intersection footprint Landscape Buffer – Landscape buffers provide visual and aesthetic function to a roundabout separating automotive and/or cycling traffic, from other forms of traffic Pedestrian Crossings (PC) – Where crosswalks are included, they shall be located a sufficient distance upstream/downstream from the entrance/exit (respectively); PC will have appropriate signage, slopes, and accessibility considerations for the visually or otherwise disabled Splitter Island – Splitter islands exist between entry and exit lanes providing pedestrians a shelter / grade separation between automobiles entering and exiting roundabouts xvii Over Tracking – The action of the rear of a tractor trailer to shift to the direction of the cab’s turn, and the trailer itself tacks ‘over’ into the adjacent lane, or trailer ‘over run’ area xviii Acknowledgements I’ve grown profound respect to the guidance of the staff and faculty at UBC. Dr. Lovegrove has continually encouraged and challenged my growth in this field; I am deeply thankful for his mentorship. I have unwavering support for family members who have supported me throughout my education. My mother has always encouraged my passions, my father has always leaned a tactful mind to technical challenges, and my daughters have always inspired me with humility and graceful curiosity. My sincerest appreciation is expressed towards my employers Ben Rawlinson, Jordan Beach, and Joshua Graff for allowing me significant flexibility to pursue career aspirations. Thank you to Ryan Boven and Joshua Richardson for their patience and mentorship. Without skills learned while at Aplin & Martin, much of this work wouldn’t be possible. Special thanks are owed to my Dutch colleagues Peter Carton, and Dr. Bertus Fortuijn, who both extended my understanding of Turbo Roundabouts significantly. Within Canada, Mr. Stephen Sargeant provided expert insight several times throughout my studies, and I am deeply grateful. xix Dedication To My Parents1 Chapter 1: Introduction Modern Canadian transportation is supported by a diverse road network; when these roads cross, intersections are needed. Single lane roundabouts (SLRs) have grown to become a standard intersection choice over the last two decades however, due to capacity their application is limited to relatively small volume crossings. Roundabouts are preferred over traditional intersections (traffic lights or stop sign crossings) due to reducing property-damage-only (PDO) collision and injury collision frequency over 35% and 75% respectively [1], and greatly increasing traffic flow. Multi lane roundabouts (MLRs) have been implemented for roughly two decades in North America however, their success does not include the sweeping safety benefits of SLRs. As time is lost within transportation systems due to ‘clogging’ of intersections and traffic backup, the need for solutions that offer better safety and traffic flow capacity exist. Turbo Roundabouts (TRs) are a relatively new intersection concept implemented in the Netherlands nearly twenty years ago; these MLRs include raised lane dividers, spiral circulating lanes, often shelter islands for pedestrians, and sometimes raised pedestrian crosswalks. While these roundabouts improve safety over existing MLR’s [2], and capacity over SLRs, the relative impact of specific TR geometry and placement of appurtenances is still being researched. Approach angles influence speeds of entering or exiting vehicles [3], and consequently capacity and safety are functions of these angles. Crossing shelters assist pedestrians and cyclists by shortening road crossing distance, while raised crossings lower approaching vehicle speeds without disrupting two-way traffic flow. With rise of active transportation in municipal communities [4], inclusion of appurtenances in designs cannot be overlooked. 2 As Turbo Roundabouts are only seemingly being built in Europe, and somewhat recognized in the U.S. via an FWHA primer [5], there appears to be a knowledge gap for Canada to promote implementation; despite some MLRs that mimic Turbo Roundabout design, there are no ‘true’ TRs existing in Canada. Due to harsh winters and large snowfall, parts of Canada might create environmental challenges for snow removal. Additionally, there are various studies that somewhat conflict with the safety benefits purported. Finally, appurtenances that make our intersections functional and desirable parts of the build environment seem to lack definition in existing design aids and research. 1.1 Research Objectives and Gaps Without any North American planning or design resources available, it was difficult to accurately know if and how Turbo Roundabouts (TRs) may perform in Canada. Relevant material was discussed to gain an understanding of TRs within a literature review. As an exercise in design and feasibility, this thesis investigated the claimed benefits of Turbo Roundabouts through a Kelowna Case Study. This thesis investigated and determined how these intersections actually performed via Europe field visits. The main research question of this research was: Can Turbo Roundabouts work in Canada, and if so, how well? This gap was examined via a preliminary understanding of the primary, secondary, and external costs and benefits associated with Turbo Roundabout implementation, and through geometric design according to available Dutch design 3 guidelines. Unknown gaps emerged throughout the feasibility design process which were previously unknown and were detailed in Chapter 5. 1.2 Turbo Roundabouts – What Are They? Turbo Roundabouts are a multilane roundabout designs with key characteristics, namely:  Spiral geometry  Raised lane dividers / lane channelization  More radial / perpendicular entry The Turbo Roundabout was developed in the Netherlands and have since been adapted in other European countries such as Germany, Slovakia, Poland, Lithuania, Croatia, Slovenia, Denmark, Latvia, Finland, and Macedonia. There are recently constructed Turbo Roundabouts in Aruba, and the United States. Canada has a ‘lookalike’ design constructed in Victoria, BC. A more detailed definition may be found within section 4.1.4.1.1, on page 72 of this thesis. A picture of a typical Turbo Roundabout may be found below, in Figure 1. 4 Figure 1 - Standard Layout of Basic Turbo Roundabout [6] Single lane roundabouts’ primary benefit is vastly superior safety as compared to traditional intersections (stop controlled, yield, signalized), while still retaining excellent capacity. Turbo Roundabouts were invented to combat safety problems that Dutch transportation engineers were having regarding conventional multilane roundabouts just before the millennium [3]. 1.3 Turbo Roundabouts – Why Do They Exist? Single lane roundabouts’ (SLR’s) primary benefit is vastly superior safety performance as compared to traditional intersections (stop controlled, yield, signalized), while still retaining excellent capacity. When retrofitting intersections to SLR’s in the US, injury collisions and total collisions dropped by over 70% and 50%, respectively [7]. Multilane roundabouts experienced significantly diminished safety benefits as injury and total collisions only dropped by 29%, and 31% (retrofit applications), respectively; this data may be shown in Figure 2, below. The Dutch had a similar, if not worse, experience regarding multilane roundabouts; the only multilane roundabout designs Raised curbs as lane dividers 5 permitted in the Netherlands are Turbo Roundabouts, due to their significantly improved safety performance. Turbo Roundabouts reduced injury and total collisions at sites in the Netherlands by 82% and 49%, respectively [3]. It should be understood that ~38% of multilane roundabout collisions are not possible due to the engineering features of a Turbo Roundabout; 38% of multilane roundabout collisions are exiting-circulating [8], and lane changes are prevented within Turbo Roundabouts due to lane dividers. Figure 2 - Collision Frequencies at US Intersections Converted to Roundabouts 1.4 Thesis Format and Structure Chapter 2 includes a contextual introduction to Turbo Roundabouts via excerpts of a conference paper, and continue into a more detailed literature review. Chapter 3 and Chapter 4 are structured as individual reports as they were portions of research that contributed towards the overall thesis. Chapter 3 included a feasibility design project within Kelowna, British Columbia, for a Turbo Roundabout design; this portion of the research was conducted early to gain understanding of potential holes in background research that were mitigated with field visits. Chapter 4 outlined environmental and cultural differences that gave rise to Turbo Roundabouts, and traffic survey data of actual TR’s. Chapter 5 discussed the materials compiled throughout the literature 6 review, design study, and field visits to provide summary conclusions for the overall thesis. 7 Chapter 2: The Case for Turbo Roundabouts and Literature Review The main literature used for this review originated from international research papers, and manuals produced in Europe; two of the main sources, while also being the most well defined, continue to be the Dutch Roundabout Design Manuals. As principal design sources, much of the research created by others to date has either supported or questioned the assertions of the Dutch manuals. This literature review analyzed the Dutch and Canadian roundabout design manuals by comparing them (primarily) with peer reviewed papers. For the purposes of analysis, this review was limited to unsignalized or self-regulating Turbo Roundabouts and mixed multi lane roundabouts. The first four subsections of this literature review will discuss features of a Turbo Roundabout that distinguish it from other similar intersection improvements. The fifth section will discuss how Turbo Roundabouts operate, their limitations, and opportunities within a transportation network. Sixth and seventh sections will review Dutch and Canadian design sources, respectively. Literature review of global design guidelines was limited to Canadian and Dutch sources, for two reasons: 1. The Dutch Turbo Roundabout design manuals are generally acknowledged by industry leaders as the global authority and recognized best practice; and, 2. The Canadian guidelines mimic the US, and consequently the Transportation Research Board (TRB) which provides the current state of practice on modern multi-lane roundabouts in NA, which this research was intended rely and build on. 8 2.1 Spiral Lane Geometry There are seven variants of lane geometry prescribed within the 2009 Dutch manual: basic, egg, knee, spiral, rotor, stretched knee and star [3]. The FWHA defines a Turbo Roundabout as having no more than two circulating lanes; and prescribed only the basic, egg, knee, spiral, and rotor geometries. The additional roundabout types in the Dutch catalogue (stretched knee and star) allowed for much higher capacity with additional lanes, which is something not recommended by FHWA [5]. Performance was mainly linked to safety statistics and not speed or volume for Dutch applications. The parameter found to be most closely correlated towards safety and speed was the radii of the inner curve and inner lane (TR1); the ideal radii was found to be 12 m [3], [9]. The inside spiral begins with TR1, ends on TR3, and may be seen in Figure 3 below, which also illustrates typical design geometry; four radii are used in laying out any two lane Turbo Roundabout, and up to six radii are used if a three lane Turbo Roundabout is desirable. The radii are offset from center along a translational axis, approximately half a lane distance. Using a smaller radii roundabout (as found in the Turbo Roundabout) ensures that vehicles will maintain a reasonable speed throughout the circulating lanes; it’s commonly understood that lower vehicle speeds drastically reduce the potential for serious injuries, however in 2012 Italian research lent credit to the roundabout design manual by suggesting 40km/h< as the optimal design speed for Turbo Roundabout design [10]. This research coincides with UK guidance detailing pedestrians are three times more likely to die if struck by a vehicle at 50km/h as opposed to 32km/h; further, accidents are more likely to be severe, and require longer stopping distances at higher speeds [11]. Slower speeds are 9 supported in both federal roundabout design manuals in the United States as being integral to the success of single lane roundabouts [1], [7]. Figure 3 - Turbo Block Detail Czech researchers examining implementation of Turbo Roundabouts found the optimal lane width for Turbo Roundabouts was between 4.5 and 5.8m in width [12]. This width coincided with values given in the Dutch Roundabout Design Manuals [3], [9], however this varied lane width allowed some flexibility to ensure that lanes were not too 10 wide to encourage excessive speed, nor too narrow to force oversize vehicle lane encroachment. Perhaps one of the most easily understood and well documented arguments for use of a Turbo Roundabout is from a conflict assessment approach; utilizing TRs in place of MLR’s drastically reduces the amount of potential conflict points within an intersection design, as shown in the figure below. Figure 4 - Comparison of Multi Lane and Turbo Roundabout Conflict Points, Adapted From [5] 2.2 Physical Lane Dividers Lane dividers are a defining component of Turbo Roundabouts. They prevent lane weaving, reduce speed of circulating vehicles, and reduce risk of being cut off while travelling in other lanes [3]. A large ‘Frog’ is placed near the start of the inner travel lane’s divider to allow higher visibility of the lane’s entrance and encourage 11 entering the appropriate circulating lane. Frogs may be seen in Figure 5, below. Figure 5 - Turbo Roundabout Frogs Reflectors are advised and may be placed either on top of the lane divider, or on slopes; reflectors are shown in Figure 6, below. The original lane dividers had a ‘soft’ raised curb of approximately 1 inch, and then a sloped raise of another 2 more inches to the total height of barrier; the soft curb allowed vehicles to pass over if required however was a significant deterrent. To allow snowplowing the overall height of the divider was unchanged, but the soft curbs were removed, as shown in Figure 6, below. The overall width of divider in both diagrams is approximately one foot wide, and a foundation or footing was suggested as a concrete structure embedded in the roadway. 12 Figure 6 - Physical Lane Dividers, Adapted From [3] In 2015, a Polish research paper investigated the effect of raised lane dividers on reduction of certain types of collisions, as compared to multilane (spiral) roundabouts with no raised lane dividers. At that time Poland had constructed both Turbo Roundabouts with and without physical lane dividers; the type and severity of collisions that occurred at the Turbo Roundabout with a physical lane divider were strikingly different; the collisions resulted in approximately 20% fewer serious injuries, and less than half the amount of vehicle side impacts when physical dividers were employed. The author concluded there was little difference between Turbo Roundabouts without a lane divider and a standard multi lane roundabout from a safety perspective [13], and suggested that multilane roundabouts without raised lane dividers are undesirable. 13 Figure 7 - Collisions Type Comparisons Between Turbo Roundabouts With and Without Raised Dividers, Adapted From [13] Safety benefits of Turbo roundabouts with a raised lane divider cannot be overstated. Another group of Polish researchers analyzed collision data of nine multilane roundabouts (five of which were Turbo Roundabouts) over four years to prescribe predictive models of safety performance factor. The data and modelling suggested a 90 percent confidence that with given traffic volumes, a raised lane divider would result in up to 60 percent less collisions at a Turbo Roundabout site [14], and most definitely in US applications where higher approach speeds are common. According to this team’s research, the likelihood of drivers to follow a swept path was highly influenced by the presence of lane dividers; up to 40% of drivers using multilane and Turbo Roundabouts violated the selected lanes and changed lanes within the 0102030405060Vehicle RearImpactPropertyDamageVehicle SideImpactOverurning OtherPercent of CollisionsCollision Typewith raised dividerswith painted line dividers14 circulating lane when no physical lane barriers were used. Having lane dividers reduces the potential conflict points significantly for circulating vehicles, and ensures that smaller radii geometry is followed, which induces lower speed and risk towards vehicles within the Turbo Roundabout. Further, Italian research demonstrated that the physical lane dividers guarantee a reduced running speed throughout the circulating lane, by enforcing compliance to the smaller radii geometry [10]. This research suggested that physical lane dividers should be used in all circumstances when considering Turbo Roundabouts in an urban context. 2.3 Approach Lane Vectors Alignment of the approach lane is a critical determinant of incoming speed. It is desirable to have drivers reduce speed when entering roundabouts for safety reasons; drivers need to slow down in advance of negotiating an appropriate entry into the circulating lane. Due to this reason it’s allowable to have offsets to the left of the center of the roundabout, but not to the right; however having an offset to the left is only advised if there are no cyclists and few pedestrians crossing the roadway, as higher vehicle exiting speed is expected [3], which may prevent drivers negotiating vulnerable road user crossings. Ensuring vehicles approach roundabouts nearly perpendicular encourages reduction of speed due to the radius of curvature to enter the circulating lane; without a smaller radius curve to enter the lane, reduced speed (and therefore safety benefits) cannot be guaranteed. 15 Figure 8 - Approach Axis Line [3] 2.4 Pedestrian and Cyclist Crossings Werner Brilon summarized lessons learned with all types of roundabouts in Germany at the 2011 TRB roundabout conference; particularly useful were the findings about effective placement of appurtenances. It was suggested that the only significant risk at compact roundabouts was with their connection to cyclists; Brilon suggested that cycle track crossings of entry and exit lanes should be placed at least 5 m from the circulating road and might only be necessary when traffic carried at the roundabout exceeds 15,000 vehicles per day. While statistical information wasn’t presented to support some of the lessons learned, it was suggested that cyclists are poorly visible when their crossing distance is too close to the circulating lane [15]. Conclusions of this paper suggested that signalized intersection is still a well accepted solution for traffic amounts above 40,000 vehicles per day. 16 Brilon’s findings were supported in a British case trial study where different cycle track and crossing schemes were tested to analyze how roundabouts affected the safety of cyclists and pedestrians and their proclivity towards active transportation in a network where roundabouts were constructed. Overall, the cyclists and pedestrians were supportive of the roundabout improvements towards active transportation. The designs most successful included segregation of all three modes, and separation from the circulating traffic ring [16]. It should be noted that pedestrian crossing locations and inclusion of appurtenances likely has significant effects on traffic capacity in urban context, if at grade crossings are included. Italian researchers estimating capacity of Turbo Roundabouts in urban context had contentious findings for capacity that did not agree with previous research and may warrant further investigation [10]. 2.5 Placement within Network and Capacity Researchers in Spain analyzed the safety and capacity of Turbo Roundabouts using gap acceptance theory along with other complex capacity formulation techniques. Generally, the findings indicated that Turbo Roundabouts had limited application in very high saturation circumstances. The researchers concluded that previous authors used much too simplistic approaches for comparison of Turbo Roundabouts to mixed multi lane roundabouts (specifically for lane allocation and saturation); the circumstances where Turbo Roundabouts perform best were found to be locations where turns in the minor traffic flow direction were above sixty percent [17]. This point was further examined and agreed upon that for Turbo Roundabout capacity to exceed multi lane roundabouts, more than sixty percent of vehicles must be turning right [18]. 17 Further research by Silva and others analyzed performance of Turbo Roundabouts compared to multilane roundabouts with microsimulation and real case study in corridor applications. The corridor analyzed had three roundabouts spaced at 400 and 470m on a two-lane road; the research was aimed at analyzing capacity of these Turbo Roundabouts at saturated or near saturated conditions. The findings by this research suggested capacity performance degrades rapidly as Turbo Roundabouts exceed capacity [19], as opposed to conventional multilane roundabouts; it appears the multilane roundabouts were less susceptible to clogging at saturated conditions. 2.6 Canadian Roundabout Design Guide (2017) Transportation Association of Canada (TAC) published the Canadian Roundabout Design Guide (CRDG) in January 2017 [20]. The guideline was essentially a summarized and condensed version of the leading American reference document, NCHRP Report 672 - Roundabouts: An Informational Guide, Second Edition. The TAC CRDG did not contain as much detailed information as it was meant for use primarily by practitioners not researchers. Chapter layouts of both manuals were nearly identical, with some authors shared between manuals, and the reference list for the CRDG’s geometric design chapter is limited to seven sources – inclusive of NCHRP Report 672. Other sources used in the CRDG were limited to Commonwealth countries of Australia, Ireland, Scotland, and New Zealand; NCHRP Report 672 sources are largely limited to Australia, the United Kingdom, and the United States itself. Given that none of the countries referenced are commonly recognized as having the safest roads, contrary to many of the Baltic states, Germany, the Netherlands, or any Eastern European countries, it begs the question if these are effective designs to be relied upon. 18 2.7 Dutch Design Manuals The Dutch created the TR design concept [21]. Moreover, they were the first country worldwide to build Turbo Roundabouts and have the most Turbo Roundabouts of any country worldwide. The safety performance of their road networks, when considering the active transportation participation and urban density, is world class. The application of Turbo Roundabouts in the Netherlands is the most experienced, and as such was relied upon for design guidance in subsequent chapters of this thesis. There are two main manuals for roundabout and Turbo Roundabout design within the Netherlands, which are summarized below. 2.7.1 Roundabouts – Application and Design (2009) Roundabouts – Application and Design was published by the Ministry of Transport in the Netherlands in 2009 [3], but written by private consultants, CROW (a non-profit national government agency responsible for infrastructure standards publications in the Netherlands), and the Ministry of Transport; collectively this manual and working group identified with the ‘Partners for Roads’ initiative, which is a knowledge sharing initiative of European countries initiated by the Dutch [3]. The manual included many lessons learned across European countries towards delivery of single and multilane roundabouts, and it has been one of the first government published manuals that provided significant guidance on application of Turbo Roundabouts. The document also acknowledged the tenets of Sustainable Safety, the Dutch safety system, similar to Vision Zero and other international road safety initiatives. The manual itself is more tailored as an introduction to design from a planning level. There is information present to understand road network planning from a 19 sustainable safety level, which may or may not be transferrable to a Canadian environment due to differences in geography, density, and policy. There is an introductory amount of information regarding planning and design for single lane roundabouts, Turbo Roundabouts, and Turbo Squares / Tables (larger scale signalized Turbo Roundabouts). 2.7.2 Turbo Roundabout Design Manual – CROW Publication 257 (2020) CROW Publication 257 was a specific Turbo Roundabout design manual written for CROW, by a number of professional practitioners; the practitioners included Dr. Bertus Fortuijn, inventor of the Turbo Roundabout [9]. The manual was written in 2020, after hundreds of Turbo Roundabouts had already been constructed and in use within the Netherlands. The manual is specific to applications of Turbo Roundabout design, and touches on the topics of road safety, geometric design, cyclist interactions, design vehicle, capacity planning, variants, etc. This is a more detailed manual than the 2009 manual by the Dutch, however the design method is somewhat rigid to the European vehicle fleet; European truck and trailer combinations are much shorter than North American truck and trailer combinations. Due to fleet differences, application of some parts of the design provided in this manual are quite limited. Signage, lessons learned, and safe system approaches are fairly novel and different than what might be found in most North American manuals. Due to variations in traffic system design (signage, demarcation, etc.), the Dutch guidance contained within CROW Publication 257 was invaluable in evaluating safety treatments prescribed from a Human Factors approach. There is limited empirical data that can be relied upon to support the safety effects expected for Turbo Roundabout intersections constructed 20 in North America, however by analyzing the human factors, there are many arguments to be made for mandating the recommended design principles within Turbo Roundabouts. Last, a difference from Canadian manuals was the Dutch approach to performance checks. Dutch design assumed that driver speed on Turbo Roundabouts will stay constant if yielding is not required on entry, which is reflected in the performance check method. Because the design prescribed in the Dutch manual is more radial (i.e. intersecting at 90 degrees) than North American tangential approaches, and minimum increase in fastest path radii is possible due to spiral design; because of the limited radii change, a simpler method of fastest path performance check may be performed which ignores radial differences (unlikely / negligible speed changes), which is summarized in Figure 9, below. Conversion formulas to determine velocity from turning radii are also different between Dutch and North American manuals. 21 Figure 9 - Fastest Path Performance Check Comparison [1], [9] Sightline checks aren’t really recommended by the Dutch manual during the design process, however the ‘straight on’ radial approach, slower circulating speeds, and consistent design parameters make these checks redundant during the design process. 2.8 Chapter Summary There were many sources within the international community that promoted the benefits of Turbo Roundabouts. These benefits included reduced delay, increased safety, reduced greenhouse gas emissions, smaller footprint, and reduced operations cost. The only country to use both Turbo Roundabouts and spiral multi lane roundabouts (Poland) has performed research which concluded that Turbo Roundabouts without lane dividers are not recommended [13]. There were some notable differences noted between the performance checks of the Dutch and Canadian 22 roundabout design guides. Finally, it seemed that the manuals produced in North America excluded best practices from any countries not within the Commonwealth or United States; this was peculiar because The Netherlands, Denmark, and other European countries are widely regarded as having some of the best road safety in the world for multimodal transportation, whereas the United States is not. Obviously, there are significant differences between the Dutch and the Canadian design methods for multilane roundabouts. A summary of the physical differences, operational observations, and safety impacts observed are provided below. Table 1 - Key Differences between Modern Roundabouts and Turbo Roundabouts 23 Chapter 3: Kelowna Case Study - Feasibility Design Project in Local Context Understanding of a topic comes after a period of familiarization and practice. To quantify potential benefits at probable Turbo Roundabout sites, or design retrofit applications, a feasibility project was undertaken within the Kelowna area. The potential benefits seeking quantification (in $CAD dollars) were anticipated reduction to collisions, travel time, and greenhouse gas emissions. It was ideal as a project to gain understanding of cost benefit analysis factors applicable to Turbo Roundabouts, and to practice design in a North American context (respective of North American fleet vehicles). 3.1 Site Background The proposed site was located at the intersections of Dilworth, Benvoulin, and Springfield Roads within Kelowna, British Columbia, Canada; the site may be seen in Figure 10, below. The intersection is two blocks south of Highway 97, a Provincial transport corridor running through Kelowna. Southwest of the intersection lies a newly constructed residential development, northwest a mall parking lot, northeast an overflow parking lot, and southeast a rural lot along Mission Creek Regional Park. The current intersection is a traffic signal with very high delay times during peak hour. All adjoining roads are defined as Core Area - Major Multilane Arterials as per the City of Kelowna Transportation Master Plan (CoK TMP) 2040 [22]. Dilworth/Benvoulin was identified as a project within CoK’s TMP for a designated DCC project, however Springfield approaches have more than twenty years of service life remaining and are not on the 24 same project list. The site area is relatively flat in all directions, sloping gently towards the Mission creek, a major waterway less than 1 kilometre to the southeast. Figure 10 - Google Earth Photo of Benvoulin (South), Springfield (East & West), and Dilworth (North) Intersection The proposed project intersection lies along the edge of the ‘Midtown’ urban center of Kelowna as per the OCP 2040 plan, shown in Figure 11, below. As per the OCP 2040, Urban centers are to offer walkable environments with equitable transit service and ‘greatest access’ to active transportation and shared mobility options. Due to excess demand, and wide crossing sizes, the state of the current intersection creates 25 a deterrent for cyclists and pedestrians wishing to use the active transportation network and is impeding the objectives of the OCP. Only three of the four approaches are crossable, and there is a lack of a protected shoulder on the arterials. This is a high priority bottleneck for active transportation within the proposed future priority cycle tracks within the 2016 Kelowna Pedestrian and Bike Master Plan [23], and a future primary cycling corridor within the 2040 Transportation Plan [22] along Dilworth and Benvoulin roads running north south. Kelowna’s Community Climate Action Plan identifies low carbon transportation options, community planning, and moving towards a low carbon future on a list of the city’s climate priorities [24]. 26 Figure 11 - Kelowna Urban Centres [25] The intersection lies on transit routes from all approaches; any design would need to accommodate bussing for a design vehicle. Finally, all approaches are truck routes, and would likely require accommodating WB-19 heavy haulers at a minimum (in alignment with provincial highway minimums [26]), however there is no official guidance from City of Kelowna regarding heavy hauler swept path considerations for geometric design. Kelowna’s Subdivision and Servicing Bylaw 7900 Schedule 4 – Design Standards - dictates geometric design requirements within the City for roadways [27]; the roads in question are classified as Core Area Major Arterials, and have a max grade 27 of 8%, design speed of 50km/hr, minimum radii of 105m, and K-values of 6 and 7 for illuminated-sag and crest curves, respectively. A typical Class 1 Arterial Parkway, applicable in this project location for all approaches, is shown below within Figure 12. Figure 12 - XS-R87 Core Area Major Arterial - CoK Class 1 Parkway [27] 3.2 Methodology The project was supervised by Dr. Lovegrove of the University of British Columbia, and Stephen Sargeant of the City of Kelowna. Mr. Sargeant is an acknowledged authority on roundabout design across Canada. Dr. Lovegrove proposed the project, and both men provided design review guidance throughout the project. The steps to move through the feasibility process were defined as follows:  Background Data Collection: find out information on the City’s land use plans, proposed site physical information, geography of the area, etc.  Feasibility Options Analysis: determine what intersection options exist at the current location by process of elimination  Conceptual Design Formulation: create conceptual designs to reflect what options remain and are practicable enough 28  Conceptual Level Planning Analysis: use conceptual designs and Sidra 9 (intersection analysis software) to determine costs and benefits of potential designs  Design Decision: Determine and select an ideal design based on parameters and customer needs  Iterative Geometric Design: Refine conceptual design to a preliminary level  Life Cycle Cost Analysis: Estimate cost to construct and provide more detailed life cycle cost analysis 3.3 Data Collection Data collection for the site included Insurance Corporation of British Columbia (ICBC) crash data, City of Kelowna (CoK) traffic counts, along with CoK asset data for as-built information, physical topography, and parcel extents. Peak hour traffic counts were extrapolated to provide an estimated AADT of 62,700 vehicles on weekdays, and 52,800 vehicles on weekends; actual peak hour turning movements may be seen in Figure 13, below. Total vehicles entering the intersection were 5,234 passenger vehicles and 91 trucks on weekdays, and 4,041 passenger vehicles and 42 trucks on weekends. Larger weekday trips indicate that this road services more commuters between Rutland (to the East) and the Landmark area or downtown (both to the West). The intersection is a conduit for travel Southbound in the AM and Northbound in the PM for traffic heading to and from Mission, Pandosy, and 29 the Okanagan College areas. Only 126 cyclists used the intersection on weekdays, along with 71 pedestrians; on weekends, cyclists were less common. Figure 13 - Peak Flow Turning Movements, Weekday PM [28] 3.4 Feasible Option Analysis The first step for feasible option analysis was to determine which intersection types could handle the relative traffic required for peak hour and would also fit within the existing intersection parcel constraints. The only options that were being evaluated for this study were: a) No improvement/change as a base case. This case includes traffic signal optimization as a best case as-is scenario. b) Rotor Style Turbo Roundabout with low angle slip lanes c) Rotor Style Turbo Roundabout 30 d) Signalized options of b and c) Sidra Intersection, version 9 was selected as the preferred planning level comparison tool to test for level of service due to ease of use, and quality of reports [29], [30]. Sidra Intersection is used by over 90 countries worldwide [31] by transportation engineering professionals for micro analysis of intersections’ traffic performance. Sidra 9 also has mechanisms in place to allow for simulation of a Turbo Roundabout, according to the instructions presented by Sidra staff shown in 0. Sidra can also simulate expected greenhouse gases produced, and travel time expended. Three-laned MLRs were not considered for this intersection due to increased collision rates that have been found at locations where they have been installed [32]; safety benefits on three-lane roundabouts aren’t well studied, but there is considerable dispute they are a ‘safe’ option at this time [8], [32]. 3.4.1 Rotor Style Turbo Roundabout The recommended capacity of a Dutch Rotor variant Turbo Roundabout, is approximately 4500 passenger car units (PCU) per hour, as per the Partners for Roads Roundabouts Application and Design manual [3]. The anticipated peak requirement for this intersection is ~5450 pcu/hr; while this option doesn’t meet existing demand it may satisfy nonpeak requirements, along with other competing CoK priorities. Figure 14, below, shows an example Rotor Style Turbo Roundabout (RSTR); RSTR are the largest Turbo Roundabout variant that may be implemented on a four-leg intersection. During initial SIDRA 9 analysis and design concept sketches, the RSTR was optimized for it being on a trucking route to only allow heavy trucks to occupy the inner and outer entry lanes only. This increased the intersection capacity and allowed it to meet most design 31 objectives. Future research should be undertaken using micro-simulation models to determine what impacts may be if allowing large trucks on all lanes. Vissim is one such software that could be used for Turbo Roundabout Simulation [33]. Figure 14 - Dutch Rotor Style Turbo Roundabout [21], Used with Permission 3.4.2 Low Angle Slip Lanes vs. High Angle Slip Lanes Low angle slip lanes (angle of merge <55°) were tested as a design option for this intersection because of limitations on capacity; high angle slip lanes (angle of merge >55°) are generally considered safer (because of lower travel speed) but don’t seem to add any addition capacity to a Rotor Turbo Roundabout. Practical Capacity: 4500 pcu/hr 32 Figure 15 - High Angle Slip Lane, Adapted From [34] High angle slip lanes are similar to ‘smart right’ turns that have recently been adopted in British Columbia for urban and suburban arterial applications, and are recommended to be placed “where it is intended that vehicles stop before completing the turn” [34]; a depiction of a high angle slip lane may be found above in Figure 15, while a depiction of a Turbo Roundabout with low angle slip lanes and signalization, respectively, may be found in Figure 16 and Figure 17, below. The letters on each approach denote forecast Level of Service (LoS) in Sidra 9. 33 Figure 16 - Level of Service (A thru E) Achievable on Rotor Style Turbo Roundabout with Low Angle Slip Lanes and Signalization 34 Figure 17 - LoS Achievable on Rotor Style Turbo Roundabout with Signalization 3.4.3 Signalization (Metering) Metering signals have been used on MLRs to preclude overloading of the circulating lanes and maintain efficient capacity; adding a metering signal can effectively balance utilization of circulating lanes in certain circumstances. Metering may be used in circumstances where platooning traffic flow patterns or irregular and unequal lane distribution on some (previous) approaches may upset access to the circulating lanes downstream. Unfortunately, to properly model the effects of platooning of nearby traffic signals, which the project site was subject to, would require network analysis within Sidra. Access to the resources required for network analysis was not available for this project. Because limited information was available to indicate the arrival flow patterns, and network analysis was not performed, it remains as future research to study if 35 metering signals would be beneficial to the level of service of this intersection. With the limited analysis performed in this current research, metering signals were not found to be beneficial in the design. 3.4.4 Analysis Findings Sidra was used for level of service (LOS) findings for all peak hour times, and off peak times for signalized and unsignalized Rotor style Turbo Roundabouts with or without slip lanes; the existing intersection level of service was also presented for comparison. Sidra created detailed reports for the potential intersection options. Select circumstances, as denoted in below Figure 18, may be found in attached Appendix C. Initial analysis suggested the best-case scenario of the potential intersections tested would be a Rotor style Turbo Roundabout (RSTR) with no signals nor slip lanes. Figure 18 - LOS Findings of Tested Intersection Options 36 3.5 Conceptual Design Alternatives The below designs were considered from a conceptual level with respect to the life cycle cost and potential alternatives to this intersection. 3.5.1 Option 1: Do Nothing Although this intersection is targeted as a problem point for the City, not only for cyclists but also do to traffic delay, the existing intersection still has much of its useful life remaining. The hardscaping and pavement is in fine condition, and the signals are operating correctly. The intersection is quite large, and any improvements will have significant impact to the capital budget for the CoK which might be deployed on multiple other smaller projects. 3.5.2 Option 2: Turbo Roundabout The Rotor Style Turbo Roundabout was the most acceptable design choice from a feasibility analysis. A conceptual plan on accommodating pedestrian and bicyclist traffic is required to accommodate all traffic modes. The BC Active Transportation Design Guide recommends that an off-road protected crossing be utilized for this type of intersection. The two types of crossings considered were a Multi Use Path (MUP) overpass, and a MUP underpass. 3.5.2.1 Option 2.1 MUP Underpass Due to conservation of energy and momentum when cycling downward, it’s usually viewed as easier to go through a tunnel rather than an overpass. Tunnels don’t need to be cleaned during snow and rain events, and provide safety during extreme weather events. Tunnels are safer than bridges in the event of an earthquake, or a lightning storm. Tunnels also have a longer service life than bridges / overpasses. 37 The disadvantages of tunnel construction begins with the need to close the roadway for earthworks; this can potentially extend weeks due to the volume of earth required to infill. The cost and timeline for construction of tunnels is typically higher than bridges, but not always. Another drawback of tunnels is a perception that they may be unsafe or seen as potential locations for crime. An example tunnel which has served the CoK well may be found adjacent to city park, and shown in Figure 19 below. “Roundabouts – Application and Design” does not recommend at grade intersections for pedestrians and cyclists at collector roads exceeding 50 km/hr design speed [3]. Figure 19 - City Park Tunnel, Kelowna 3.5.2.2 Option 2.2 MUP Overpass The CoK has multiple examples of pedestrian overpasses within the community; the MUP in the Landmark area is one example of how to accommodate pedestrian and cyclist traffic. Advantages of overpass construction include limited road closure 38 requirements to install the MUP overpass itself, likely lower cost, and a lower impact on shallow utilities. Disadvantages of a MUP overpass include long, sloped access ramp requirements due to minimum bridge clearance heights, Accessibility Canada Act (ACA) requirements [35], and best practices set by the BC Active Transportation Design Guide (BC ATDG) [36]. Height requirements for any CoK bridge are 5.0m above roadway surface, as per BC MOTI design guidelines [26]. Multi-use path grades should be less than 4%, and ideally under 2%, as per BC ATDG. To meet grading and height requirements, each access ramp would likely require over 125m in length and require extensive property acquisition. 3.6 Design Selection Analytical Hierarchical Process (AHP) was used via survey feedback from two (2) City of Kelowna Transportation Planning Engineers; this process helped determine project goals with respect to cost, safety, sustainability, accessibility, and ambience. Results of the AHP rating identified the priorities of the CoK were mainly Safety and Accessibility, as shown in ‘Relative Weight’ of the AHP figure below. 39 Figure 20 - AHP Determination for Transportation Priorities Within The City of Kelowna Using AHP, a ‘scoring method’ was developed to apply weights to the relative characteristics of the conceptual design alternatives; utilizing this method, the design could be determined based on the city’s goals. The results of the MAE analysis may be found in the below Figure 21, and recommended a MUP underpass option. Figure 21 - Multiple Account Evaluation (MAE) of the Conceptual Design Alternatives Using AHP Criteria Cost Safety Sustainability Accessibility AmbienceA Cost 1 0.167 0.5 0.25 0.5B Safety 6 1 2 1 4C Sustainability 2 0.5 1 0.5 0.25D Accessibility 4 1 2 1 4E Ambience 2 0.25 4 0.25 1F Sum 15 2.916667 9.5 3 9.75Criteria Cost Safety Sustainability Accessibility Ambience Relative WeightA1 Cost Normalized 0.07 0.06 0.05 0.08 0.05 0.062B1 Safety Normalized 0.40 0.34 0.21 0.33 0.41 0.339C1 Sustainability Normalized 0.13 0.17 0.11 0.17 0.03 0.120D1 Accessibility Normalized 0.27 0.34 0.21 0.33 0.41 0.313E1 Ambience Normalized 0.13 0.09 0.42 0.08 0.10 0.165SUM 1.00Lambda5.4619045.678115 CI 0.1915.082326 RI 1.1205.764432 CR 0.1715.65691AHP Overall Priority DeterminationMAX = 5.764431731FACTOR WEIGHTS DO NOTHINGMULTI USE UNDERPASSMULTI USE OVERPASSCOST 0.062 10 3 5SAFETY 0.339 1 8 8SUSTAINABILITY 0.120 5 10 10ACCESSIBLITY 0.313 2 10 8AMBIANCE 0.165 2 7 10TOTAL 2.52 8.39 8.3840 To explain scoring, both options were sustainable. Accessibility was determined to be worse for the overpass due to long ramp lengths, and lack of conservation of momentum for cyclists. Cost was slightly better for an overpass versus an underpass, due to constructability. An overpass was viewed as potentially more aesthetic than an underpass as the CoK has already demonstrated pleasing bridges constructed within the last two decades. 3.7 Preliminary Geometric Design A preliminary drawing set of the proposed Turbo Roundabout with MUP underpasses may be found in Appendix D , with a sketch excerpt shown below in Figure 22. Lessons gleamed from geometric design are shared below in subsections. 41 Figure 22 - Turbo Roundabout Sketch with MUP Tunnels 3.7.1 Minimum Radius and Lane Width Circulating roundabout lanes (Turbo or otherwise) cannot be too wide as this allows smaller vehicles the ability to weave more freely, especially within multilane applications (finding a significantly faster path). The importance of lane-width is shown 42 in Figure 23 below, which depicts an MLR as opposed to a TR, where the absence of lane dividers often leads to higher speeds, and more frequent speed changes. Circulating lanes also may not be too narrow if both lanes are to be utilized simultaneously by different vehicles, which is intended with Turbo Roundabout applications. Figure 23 - Fastest Vehicle Path through Multi lane Roundabout In circumstances where there are very long wheelbase design vehicles, such as a WB-21 (common in British Columbia and Alberta for shipping) – a challenge exists translating dimensioning from a European / Dutch context; European design vehicles often dictate much smaller tractor wheelbases, coupling distance, width, and consequently, overall turning radius (swept path). 43 Figure 24 - Canadian WB-21 Profile Dimensions [37], Used with Permission Figure 25 - Canadian WB-21 Plan Dimensions [37], Used with Permission Figure 26 - Canadian WB-21 Turning Profile [37], Used with Permission It is not possible for a WB-21’s trailer to fit within a 6m swept path, unless the outer front turning radius is ~35.5m; dimensions of this size this would create roundabouts (and Turbo Roundabouts) with fastest paths on multilane roundabouts exceeding 50km/h, and inscribed circle diameters exceeding 70m. This is prohibitively large and negates the safety aspects of inducing curvature on drivers to reduce speed. The “WB-21 Problem” is not apparent within European Turbo Roundabout design as their fleet vehicles often dictate much smaller tractor trailer effective wheelbases for 44 shorter trailers, a smaller coupling distance, shorter tractor width, shorter overhang on tractor vehicles, and an overall smaller swept path. The ‘worst case’ wheelbase dimensions for European design vehicles are shown in Figure 27, below. This depicts a tractor trailer combination with a maximum length of <17m this is up to 8.5m shorter in overall length, and >4m shorter in effective wheelbase. This allows Turbo Roundabout lanes to be narrower than 5.5m within the Netherlands, and have an outer ICD of <23m. North American tractor trailers are also wider than their European counterparts by 0.1m. Because of the size discrepancies from North America to European design vehicles, the swept path for a North American long tractor trailer is wider, and the roundabout requires a larger inscribed circle footprint to accommodate a similar flow through capacity. The below figures show the plan dimensions of WB-21 vehicle, and the swept path figures for the trailer may be found in the attached Appendix B, along with a small snip of a similar Turning Template for the inner radius below. Figure 27 - Dimensioning Vehicle for European Roadway Roundabouts [21], Used with Permission 45 3.7.2 Over Tracking Lanes Over tracking is the tendency for the trailer of a tractor-trailer to drift in the direction the cab is turning. This problem becomes very pronounced with long trailers and smaller radius turns. It would be very challenging to design a safe rotor style Turbo Roundabout that incorporates over tracking for very large design vehicles in urban (space conscious) circumstances, because: a) The lane width may be compromised (made wider) to accommodate large vehicles at the expense of keeping the speed lower for more common smaller vehicles. This would result in an excessively large design against the desired objectives. b) On the inner lane, large vehicles can track inward. On the outer lane, large vehicles can track in and outward. This research found concerns about the turning radius and subsequent overtracking (in or out) or lane widening, that would be necessary for through traffic that are similar to WB-21. Specifically, large trucks (i.e., freight with one or two trailers) should be able to navigate the intersection side by side when in parallel lanes, if that is how the intersection permits traffic, and three side by side, large tractor trailers, if allowable. In the case of a three-lane TR, the middle lane may have issues conflicting with the inner lane; hence, it was NOT advisable to allow large trucks to navigate the middle lane, for through or left turning movements. The geometric design was constrained by having to accommodate a WB-21 design vehicle, which is shown in Preliminary Case Study Design Drawings. Utilizing a WB-21 truck on this route increased the minimum radius recommended on the intersection; 46 Transoft’s TORUS software was used for the initial intersection plan layout; this software aided considerably in repeatedly prototyping the intersection for different design vehicles, and for various shifts in the alignment to ensure ALR land wasn’t impacted for final design. 3.7.3 Constrained Use Lanes As noted previously, not allowing large trucks (such as WB-21) on the middle lane of a Rotor Style Turbo Roundabout is one method to prevent excessive TR size or lane width in this application. While using SIDRA to confirm adequacy – and checking through restricting large trucks to the inner and outer (right hand turn only) lanes with projected traffic flow, it was discovered that a significantly higher level of service could be offered if the central lane was limited to smaller vehicles only. While this may initially seem like a benefit, it would likely be challenging to ensure tractor trailer drivers are aware well enough in advance, and have adequate space, to change into the appropriate lane. Adequate signage in this use case (for very large trucks, and specific lane constraints, on a three wide lane roundabout) is paramount to prevent safety risk. 3.7.4 Fastest Path Analysis and Expected Speed A fastest path analysis revealed both lanes to be approximately 30-32 km/h as per the Kansas State Roundabout Design Manual [38], and may be found within Appendix D. Contrary to the fastest path analysis indicated through application of formulae from the Kansas State Roundabout Design Manual, the Roundabouts – Application and Design manual published by Ministry of Transport of The Netherlands indicates speed closer to ~40km/h. Clearly there is some discrepancy for calculation of flow-through speed between North America and The Netherlands. 47 3.7.5 Notes to Application on Smaller Intersections It should be noted that many more intersections could be candidates for retrofit to Turbo Roundabouts (with smaller footprints) with radii smaller & similar to Turbo Roundabout design radii as presented in the Dutch Roundabout Design Manual. A comparison of the design radii used in this project, versus the design radii presented in the Dutch Roundabout Design Manual, along with their application to the Turbo Roundabout block, may be found in Table 2 and Figure 28 below. Table 2 - Rotor Roundabout Dimensions [3] CharacteristicThis DesignR inside of inner lane R1 12 15 20 14.58R outside of inner lane R2 17.25 20.15 24.95 19.85R inside of central lane R3 17.55 20.45 25.25 20.15R outside of central lane R4 22.55 25.35 29.95 24.95Rinside of outer lane R5 22.85 25.65 30.25 25.25R outside of outer lane R6 27.8 30.5 34.9 29.637-39 38-39 40 38Radius Measurment of Rotor Roundabout (m)Rotor Roundabout DimensionsNetherlands Guidelines0.35Physical barrier between driving lanesWidth Overrun area for vehicles with length 22 to 27mSpeed Passenger Car48 Figure 28 - Turbo Block Layout for Rotor Roundabout 3.8 Economic Analysis The below subsections detail the safety benefits, travel time benefits, environmental benefits, and capital costs for the subject concept to identify a net present value of the intersection. 3.8.1 Safety Benefits It is common for transportation collisions to be stratified into groups varied by injury level; the KABCO system is the most common system used, as it is what is recorded in police data. KABCO is utilized as “crash costs are primarily a function of their severity” [39]. A definition of the KABCO system may be found in Table 3, below. 49 Table 3 - KABCO Injury Level Classification Table NCHRP Report 492 details and classifies relationships between various KABCO proportions of collisions and classifies them into a relationship table based on severity index (SI); a rendition of this table showing the scales of SI is shown in Table 4, below. Table 4 - Relationships of Severity Indexes and Injury Levels Public collision data is limited in BC, however, the data available does indicate whether collisions are PDO or have a casualty (injury). When reviewing the collision data of the subject intersection [40], it was found that the collision profile indicated that the SI of 3. A breakdown of those collisions may be found in Table 5, below. Abbreviation MeaningK Fatal InjuryA Severe or Incapacitating InjuryB Moderate or Non-Incapacitating InjuryC Minor or Possible InjuryO Property Damage Only (PDO)Injury Level Classification TableNone PDO1 PDO2 C B A K0 100 - - - - - -0.5 - 100 - - - - -1 - 66.7 23.7 7.3 2.3 - -2 - - 71 22 7 - -3 - - 43 34 21 1 14 - - 30 30 32 5 35 - - 15 22 45 10 86 - - 7 16 39 20 187 - - 2 10 28 30 308 - - - 4 19 27 509 - - - - 7 18 7510 - - - - - - 100Injury Level (%)Severity Index (SI)50 Table 5 - Collision Data of Benvoulin, Dilworth, and Springfield Intersection The 2018 collision cost calculations for Fatal, Injury and PDO collisions are given by ICBC for residents of British Columbia [41], and may be found prorated in Table 6, below, along with expected yearly collision cost benefits. The safety benefits of an intersection with this SI and expected collision cost reduction are formidable. The expected collision reduction amounts are taken from Dutch data [42], [43] on built Turbo Roundabouts converted from a combination of signal, yield, and stop control. Table 6 - Anticipated Yearly Collision Cost Benefits Intersection Collisions YearCollision CountAverage Yearly (excl. 2020)Average % of Collisions (excl. 2020)2016 432017 442018 392019 462020 232016 492017 602018 402019 382020 21Collision Count at Dilworth, Benvoulin, and Springfield IntersectionProperty Damage OnlyCasualty4346.7548%52%51 3.8.2 Travel Time, and Environmental Benefits Sidra was used to model the travel time and environmental impacts of the existing and proposed intersection. To accurately model the intersection, a distribution was applied of the existing traffic counts for weekday and weekend volumes by stratifying the traffic distribution expected for different time periods, as a percent of the daily expected traffic flow. The daily expected traffic flow was provided through counts or extended from profile data / peak flow. This data exercise was done for weekdays and weekend. Seven different hourly flow volumes were modelled for weekday volumes, and eight flow volumes for weekends. The diurnal pattern selected to anticipate traffic flow for periods not counted was through the 2011 congested corridors report, published by the Texas Transportation Institute [44]. A roadway with more than 10 hours of congestion a week, and a length of less than one mile, was the definition used for congested corridors; this report seemed appropriate for projecting traffic patterns of the proposed project – and the weekday/weekend volume patterns may be found in Figure 29 below. 52 Figure 29 - Weekday and Weekend Traffic Distribution Profiles, Adapted From [44] Double Peak Pattern for Weekdays Single Peak Pattern for Weekends 53 Next, the volume profiles were stratified and applied to weekday and weekend traffic; peak flow traffic (actual physical data) and total daily traffic being was used as a baseline data. Table 7, below, shows the traffic distributions used. Table 7 - Stratified Distribution of Daily Traffic The above patterns were modelled in the existing and proposed intersections and provided insight into the weekday and weekend costs associated with the existing and proposed intersection. Costs were extended based on Sidra default values for travel % of Flow Iteration Car Volume Truck Volume % of Flow Iteration Car Volume Truck Volume2.00% 1 1226 34 2.00% 1 1048 161.00% 2 615 20 2.00% 1 1048 161.00% 2 615 20 1.00% 2 527 111.00% 2 615 20 1.00% 2 527 111.00% 2 615 20 1.00% 2 527 112.00% 1 1226 34 2.00% 1 1048 164.50% 3 2752 69 3.00% 3 1567 196.50% 4 3976 103 4.00% 4 2090 246.00% 5 3667 89 5.00% 5 2610 266.00% 5 3667 89 6.00% 6 3130 316.00% 5 3667 89 7.00% 7 3652 346.00% 5 3667 89 7.75% 8 4036 346.00% 5 3667 89 7.75% 8 4041 428.50% 6 5234 91 7.75% 8 4041 428.50% 6 5193 125 7.75% 8 4041 426.00% 5 3667 89 7.00% 7 3652 344.50% 3 2752 69 6.00% 6 3130 314.50% 3 2752 69 5.00% 5 2610 264.50% 3 2752 69 4.00% 4 2090 243.50% 7 2141 55 3.00% 3 1567 193.50% 7 2141 55 3.00% 3 1567 193.50% 7 2141 55 3.00% 3 1567 192.00% 1 1226 34 2.00% 1 1048 162.00% 1 1226 34 2.00% 1 1048 1661200 1510 52212 579Weekday Volume Weekend VolumeSum Sum54 time cost, vehicle distribution, and anticipated emissions. A summary of the cost comparisons can be found below in Table 8 and Table 9, found in the chapter conclusion. Table 8 - Travel Time Cost & Emissions - Existing vs Proposed The travel time savings seem significant however they likely require further review to verify that hourly rates are in line with provincial guidance. Upon review with local transportation professionals, the modelled stop line delay times found using Sidra for Peak PM traffic were within reasonable expectations. Using the federally provided social cost of greenhouse gas emissions guidance [45], also provides a significant monetary benefit over the existing intersection, as shown above. 3.8.3 Capital Cost Estimate Construction costing was made possible through resources provided by Aplin & Martin Consultants Ltd, which were based (primarily) on current construction bids on civil tendered works, along with supporting mechanical and electrical work scopes as required. Final estimate of capital expenditure (including construction management, engineering, etc.) was assumed to be ~$15,530,000.00. These costs should be viewed 55 as a ±35% due to uncertainties on final scope requirements, actual demolition requirements, and potential unforeseen circumstances. Final construction cost estimate may be found in Appendix E ; due to confidentiality and professional constraints, detailed cost information regarding unit rates has been redacted. Inclusions: Excavate & backfill, asphalt removal, paving, median concrete, concrete curbs throughout, asphalt multi use paths throughout, retaining walls, concrete box tunnels, relocation of shallow utilities (including fibre optic), concrete aprons, street and tunnel lighting, municipal signage, erosion control measures, Exclusions: Approach re-grading of neighboring properties, upgrading requirements of municipal utilities that may be required when exceeding maximum depth of cover for piping, traffic control, shoring if required. Capital Cost Inclusions: engineering (Civil, Mechanical, Electrical, Site Development), construction management, economic conditions, contractor experience, material storage, overtime allowance, Insurance / Builder’s risk / WCB / Performance bond, construction progress documentation, permits, quality control testing, temporary barricades and enclosures, security, project signage, subsurface drilling and sampling, and Taxes (7%). A full breakdown of the capital cost estimate may be found in the Appendix F Appendix F of this report. The detailed construction estimate may be found in Appendix E, with confidential information redacted. 3.9 Chapter Conclusion A feasibility design was completed in Civil 3D to determine how a Turbo Roundabout might perform, anticipated earthworks, and what the potential benefits may 56 be using analysis software. It was determined through this portion of research that there were gaps in the geometric design of a Dutch Turbo Roundabout when accommodating North American fleet vehicles. The capital cost was estimated at ~$15.5 million dollars (+/- 30%) during the Class D opinion of probable costs. Economic benefits included $12.6 million dollars annually with approximately $6.2 million in safety benefits, and ~$6.4 million in travel time and environmental benefits. Table 9 – Annual Costs and Benefits Summary 57 Chapter 4: Europe Field Visits – Dutch Case Study As part of this research, these intersections and the underlying transportation culture were visited within the Netherlands. Witnessing these intersections in operation added a dimension of understanding and proof of concept to physically see how they perform, identify driver behaviour differences, and understand where the different variants might be most effective. From a review of the literature, western European transportation authorities and designers have been committed to Vision Zero and Sustainable road safety for decades before those in North America. EU designers accept that drivers make mistakes and so designs must be created knowing that road user safety is a boundary condition to active transportation and public health. In other words, transportation is a social determinant of health. The multimodal transportation, and specifically, cycling infrastructure provided to provincial and local roadways is very functional for daily commuters. On street cycling amenities are more common, including privately supplied end of trip facilities; the built environment doesn’t permit as much at grade car parking compared to North American urban environments. Traffic signals are used as a ‘last resort’ rather than a ‘first choice’, and priority rules for cyclists within municipalities often favor cyclists for stop and yield controlled intersections; as a non-signalized intersection choice, Turbo Roundabouts are often the gateway intersection between provincial highways to local arterials. Because of increased density, available amenities, preferential active transportation policies, trip times within EU communities are often shorter, greener, and more enjoyable whether taken by transit, bicycle, walking, or car. 58 This case study involved a field visit to The Netherlands and reviewed the political, economic, and environmental conditions that precipitated Sustainable Safety, and what that means for their transportation networks. It will be focused to road networks primarily, as they’re the most commonly used transportation within Canada, and can often pose as barriers for vulnerable road users. Later within this chapter, the case study will review field visits to different roundabouts in the Netherlands (mainly Turbo Roundabouts), including traffic flow, directional distribution, and speed. Finally, it provides discussion and conclusions on what Canada could do to improve their transportation infrastructure and promote sustainably safer travel. 4.1 Background 4.1.1 Origin of the Road Network and Topographic Context There are fundamental differences between North America and the Netherlands from a topographic context, and a historical context. Canada was colonized much later in history from a society that wasn’t as technologically capable for long distance travel. In contrast to the mountainous terrain of large portions of Canada, the Netherlands would fit into an area a bit bigger than Vancouver Island, is consistently flatter although similar in climate, but overall, easier to design to fit the needs of society. While Canada is the second largest country (by area) in the world, a majority of the country is undeveloped, and a large portion of it rests within the arctic circle. The various mountain ranges within British Columbia proved significantly challenging for settlers, especially during winter months; these same areas were problematic with construction of various railways, including the Trans Canada Railway (completed November 1885). Upon completion of the Trans Canada railway, it was possible to bring 59 goods back and forth between the East and West of Canada, and their respective ports for trade; much of the federal highway network constructed to date lies directly adjacent to the Trans Canada Railway, or trade routes of national importance. Ultimately, Canada was founded as a colony to export resources for trade, and much of its legal and physical structure remains as such. The Netherlands had a longer written, technological, and cultural history. Julius Caesar is the first known conqueror of the Netherlands. The Franks followed after the Roman Empire’s collapse; a few hundred years later, the Holy Roman Empire conquered the area again. After 1000 AD the country accelerated technologically as polders (low lying tracts of land) were dyked and drained via canals and windmills (for pumping) more frequently; between the 14th and 16th centuries the Netherlands became the most powerful trading country in Europe. The increase in power for the Dutch can be seen mainly as a by-product of the advances in maritime transport, and the access to ports within the country. The Netherlands was the wealthiest, most accessible, most traded with, country in the world lying within the most technologically advanced continent on Earth just prior to the Industrial Revolution. Because of these specific advantages (wealth, agreeable climate, density, access to coastline, trade relationships, flat topography), the Netherlands was an ideal place to receive cultural side effects of the Industrial Revolution. The Netherlands is primarily a river delta of the European Continent, and as such, very flat and sandy. A majority of the country’s land was formed as estuaries of three rivers: the Rhine, Meuse, and Scheldt. Because of the flat and low-lying terrain, the country is acutely susceptible to ocean flooding; because of the lack of bedrock 60 underlying most of their landmass, much of the built environment is susceptible to differential settlement. As a result, and confirmed by firsthand evidence during our research field visit, construction methods for a typical single family home include piles for the foundation to prevent settling of the house. Municipal roads often require re-construction every five to ten years, as the roads settle and sink over time. 4.1.2 Political Context Shaping Road Policy Changes 4.1.2.1 Sustainable Safety – The Dutch Model While the Netherlands has (in recent history) always been a cycling country, car ownership rates rose from 1 in 20 in 1950, to 1 in 2 in 1975 following the end of the second world war and rebuilding of Europe [46]. Increased demand and use of automobiles for commuting resulted in more auto-centric use of public space, however, contrary to many North American countries, citizens opposed livability changes required by automobiles; It was during the early 1970’s that significant strides were made towards livable streets, bicycle paths, HOV lanes, and traffic calming. During the 1970’s there was also political left and right division on whether the driver was at fault or that the system of road use (which pitted strong versus vulnerable road users) itself was dysfunctional; as automobile use was increasingly more common, this political conflict coincided with the rise in both young cyclist and auto-driver related deaths and injuries. From the 1970’s through the 1990’s, the SWOV (National Scientific Institute for Road Safety Research, Netherlands) and the Federal Road Safety Council pursued, vehicular crash reductions; however, past this period safety improvements studder stepped. It seemed there wasn’t a cohesive set of policies that could reduce road risk. This was a slight paradigm shift from the 1990’s onward which might be summarized by 61 widespread acknowledgement that, “humans are the weakest link in the road safety chain”, followed by “it’s easier to adapt the road traffic system to humans, than humans to the road traffic system”. A better way to describe this was that – if safety risks exist in the traffic network, it’s probably the system, not the user creating the risk. The focus of the Dutch Sustainable Safety program was to ‘avoid hazards instead of controlling them’ [46]. The guiding principles of Sustainable Safety’s first publication (the Purple Book) were: 1) Mono-functionality of roads; 2) Homogeneity of speed and mass; and, 3) Predictability. Sustainable safety was implemented across federal, provincial, and local levels of government in 1997, and contained twenty-four measures and actions, including: stricter enforcement, 30/60 km/h zones, permanent extensive road user education, and uniformity guidelines, among others. Unfortunately, shortly after its start, federal responsibility was distributed provincially for many legislative requirements related to road use/safety [46]; since legislative change there has been limited upward momentum in the adoption or innovation within SWOV’s policies or collaboration between provincial / municipal bodies. Regardless, the program has been considered successful as traffic-related fatalities were reduced by over 50% in its first ten years on local roads (30km/h zones) [47]. It should be noted that Sustainable Safety is a set of policy recommendations as part of a program adopted by various public agencies via binding legislation – the program did not start as legislation, and did not start as a public institution; it was created by experts and adopted by others. There is no single legislative act or policy that was created to reflect the various recommendations of SWOV. Sustainable Safety was a resource used to shape policy and legislation, not vice versa; the resources were 62 written by recognized experts in their respective fields. The adoption and collaboration between different agencies (synergy) is what made Sustainable Safety a successful program; people were willing to take a chance and adapt policy to new evidence, a critical factor to its success. 4.1.2.2 Vision Zero – The Swedish Model ‘Vision Zero’ is a term related to road safety policy understanding that the bodies responsible for road design, construction, and operation have a duty to create road systems that are safer; the ‘Zero’ part of the name is a reference to Claes Tingvall’s response to being asked how many deaths should result from child restraints being designed by his company [48], and later went to mean safety should be a boundary condition for mobility to develop (as a secondary benefit). Being that auto collisions are one of the fifteen leading causes of death in the developed world, ten leading causes of death in the developing world [49], and leading cause of death for young people aged 5-29 [50] – the importance of safety within road systems cannot be understated towards reducing preventable death. Implemented in Sweden in 1997, the policy and mindset of Vision Zero spread across Europe and the world. Although not directly a policy in the Netherlands, and lacking some framework towards implementation – the Vision Zero goal re-emphasized the importance of improved safety on the European stage at a time when Sustainable Safety was coming into its own. 4.1.2.3 Canadian Road Safety Strategy 2015 (2011) Canada’s Road Safety Strategy 2015 was written by the non-profit organization Canadian Council of Motor Transport Administrators (CCMTA), and superseded earlier Transport Canada documents and oversight. Unfortunately, the 2015 document 63 removed percentage collision reduction targets at the national level, and transferred responsibility to Provincial and local jurisdictions to determine what ‘best practices’ would be relevant to address their own road safety concerns. Despite the lack of a national road safety vision, the CCMTA document does provide generally ‘proven’ initiatives for each applicable risk group for road users, infrastructure, and vehicles [51]. 4.1.2.4 CROW Dutch Resource Library Vs TAC Canadian Resource Library CROW is the Dutch national coordinating body and technical resource library for urban planning, transportation design, and infrastructure. They provide empirically backed design guidelines to promote sustainable infrastructure in the Netherlands, however also provide access to their content (via publishing) worldwide. CROW first started publishing bicycle design manuals in the 1970’s and is an advisory body for the Dutch federal Directorate General for Public Works and Water Management (ministry responsible for all canal, road, and rail transport). In contrast, similar Canadian transportation design guidelines have been developed by the Transportation Association of Canada (TAC). TAC is a non-profit national technical association, similar to CROW, but comprised of industry, academia, and local government members. TAC superseded an older Canadian organization called the Canadian Good Roads Association, which was mainly concerned with establishing a better road network – and constructing the Trans Canada Highway [52]. Main differences exist in the origin of the two organizations, particularly the oversight each one has in the domain of overall transportation, and origin of the body itself. TAC mainly focuses to serve roadways, while CROW serves all public works. 64 4.1.2.5 Division of Roads Ownership between Governments Roadways within the Netherlands are divided into three jurisdictions municipal/regional, provincial, and federal. These political bodies are mainly responsible for three road classifications: local/access roads, grey/collector roads, and through roads. As provincial roads make up a majority of the grey roads (primarily responsible for distributing or collecting highway traffic to and from local roads) and are often found in situations where highways meet rural municipal boundaries, these (provincial) highways are the most likely candidates to benefit from the use of Turbo Roundabouts as an intersection design option. Municipal intersections might not get enough traffic or have enough space in an urban environment to demand a Turbo Roundabout; Federal freeways as through roads would not be suitable for compact intersections, let alone where slowing down and speeding up are required. Within Canada, things are much different. Highways connect municipalities directly in many cases and may or may not be pathed directly through city centers. Highways may also be owned by either the federal or provincial government, however there is little distinction in functionality between them in many places outside of major urban centers19. Federal highways are often dictated based on (traditionally) important trade routes or national security, not function. Canadian Provincial Highways would likely not be considered through roads as defined by Sustainable Safety in the Netherlands; an example of this would be the provincially controlled Highway 97 running through the Okanagan Corridor of multiple townships and cities. 4.1.2.6 Education and Licensing Differences 65 Although not compulsory in the Netherlands (NL), obtaining a (Class B) driver’s license isn’t remotely common without candidates undertaking driver training. Within the NL, drivers-in-training typically obtain forty-two (42) hours of driving lessons prior to practical testing. NL Licensing is composed of two tests: a driving-theory multiple choice portion, and a practical driving test. The minimum age for theory testing is sixteen (16), and seventeen (17) for practical exam; upon successful testing of a practical exam, drivers are granted a ‘beginner’ (provisional) license, must drive with a guardian (who is listed on their license) present until the age of 18, and will have their license revoked if they commit two serious offences, such as:  Excessive speeding (>30km/h over speed limit)  Blood alcohol content of 0.2/ml or above  Causing injury collision  Tailgating The provisional license period lasts five years [53]. First time practical tests in the Netherlands have ~50% failure rate. Driving instructors require a diploma from The Dutch Institute of Certification and Examination for the Mobility Sector [54]; mandatory instructor training, and dual control vehicles, are required to provide lessons in the Netherlands. Instructors require periodic re-training to maintain licensed status. From ages eighteen (18) to sixty-five (65), drivers license are valid for ten years in the Netherlands [55]. For older road users, drivers over the age of seventy five (75) must submit a declaration of fitness when applying for a new or renewed license, that will last a maximum of five years [56]. This declaration must be completed by a doctor and will assess: 66  Mental conditions  Epilepsy  Balance disorders  Eye diseases  Prescriptions that may affect driving ability  Blood pressure concerns  Physical capability (Visual acuity, mobility, and hearing) The declaration of fitness is valid for five years unless the doctor provides less time upon the declaration. In Canada, lessons are not compulsory either. License testing for Class 5 licenses consists of a theory test, and practical driving test, similar to the Netherlands. Minimum testing age for theory is sixteen (16) in most provinces, similar to the NL, and the graduated (provisional) licensing program may begin earlier, typically at seventeen (17), upon successful practical driving test. Provisional licensing typically lasts for one (1) to two (2) years, as opposed to five (5) years in the Netherlands; Canada has different demerit tracking than the Netherlands, with some offences qualifying immediate revocation of a provisional license. Provisional licensing requirements vary based on Province, and may include:  Driving curfews and supervisory requirements therein, if allowed  Blood alcohol limits on driver, and sometimes passengers  Maximum amounts and minimum ages of passengers  Driving infractions 67  Driving curfews Drivers’ licenses are typically renewed every five years in Canada regardless of province. For the elderly, once drivers are aged seventy-five (75) to eighty-five (85), depending on province, the following may be required to obtain licensing:  Medical examination for cognition, eyesight, and physical health, by a licensed medical health practitioner (doctor or nurse)  Driving record review  More frequent periodic review (every two years) Some provinces, such as Saskatchewan, have no age-related requirements to retain licensing. Manitoba only requires more frequent renewal periods for seniors. Ontario requires only a vision test and a group education session of 45 minutes to renew a drivers license. Alberta requires medical exams every two years past the age of eighty (80), while the age limit for the same exam/renewal in British Columbia is eighty-five (85). In Nova Scotia, drivers ages sixty-four (64) must complete annual declarations, upon which medical information may be requested by the licensing body. New Brunswick residents aged sixty-five (65) and older aren’t allowed to operate vehicles before nine AM and between three and five PM. Driving instructor mandatory training varies by province. Driver testing is typically performed by provincially certified assessment officers, of which the requirements vary. Some provinces (such as Ontario), have elected to subcontract licensing facility operation to private corporations; incidentally, there has been reported inconsistency in 68 pass/fail rates operated within Ontario [57]. It’s unclear how consistency in testing administration is maintained nationally within Canada. 4.1.3 Environmental Context 4.1.3.1 Weather Anecdotal discussions with residents within the Netherlands revealed that snowfall isn’t typically something that stays around for extended periods of time during winter (anymore); average mean temperature per month in the Netherlands may be found in the below graph for Utrecht and confirms that there are no months where snow typically stays frozen on the ground in the Netherlands. The data provided also suggests that mean temperature has risen measurably the previous two decades, compared to the prior four (roughly); this data supports what older residents had reported regarding snow when they were younger. 69 Figure 30 - Temperature and Precipitation Graph, with Data From The World Meteorological Association for Utrecht, [58] Due to the lack of snowfall and below zero temperatures, frozen roadways or plowing is not a concern within the Netherlands. As a result, there are typically more blocks (as opposed to monolithic curbs), bricks (as opposed to asphalt pavement) and vertical obstructions found within Netherlands roadways; bricks and other in-road stones often act as tactile traffic calming engineering features. The same cannot be said for Canada; typically, roads in Canada are plowed as this is the most cost-effective way of clearing snow within the roadway. Due to mean daily temperature and snowfall varying significantly at different locations within Canada, 70 consideration for snow plowing or removal (if needed) is a functional requirement for roadways and intersections. With snow plowing comes requirements within the roadway to allow for snow storage at horizontal locations a plow cannot proceed past, unless snow removal occurs (which is considerably more expensive and labour intensive) – or the road is salted (which may be environmentally constrained from occurring). Figure 31 - Temperature and Snowfall Graph [59] From the above weather data from Peachland, it’s shown that average monthly snowfall has been higher in this area the last decade; for roads, snowfall volumes during major events should be considered for snow clearing and storage requirements in Canadian urban areas. For municipalities, climate change may mean larger (or 71 smaller) clear spaces between sidewalks and travel lanes in some areas, or budgeting for snow removal. 4.1.4 Technological Context 4.1.4.1 South Holland Highways Group of the 1990’s and Early 2000’s Turbo roundabouts were invented by Dr. Bertus Fortuijn while he was studying at TU Delft and managing a working group of engineering professionals for public works (highways) at the Province of South Holland. The implementation of Turbo Roundabouts as a collection of design elements was not ‘all at once’, and some of the design elements were determined via trial and error. An example of this was determining the ideal height of lane barrier curbs separating circulating lanes; different height curbs were constructed and driven over to determine an ideal height of discomfort without necessarily causing loss of vehicle control. Through interview with the inventor of the Turbo Roundabout, and some of his esteemed colleagues, the author learned that the Provincial Highways of South Holland engineering team had a function of design and stewardship, and a budget reflecting this; they were allowed to research, develop, implement, and monitor novel changes to roadway design. Because of their progress in this field, many other provinces in the Netherlands benefitted by adapting the designs to suit their areas. Because Dutch provincial highways serve to distribute through traffic to local roads, and often lie on the fringes of urban areas (usually providing ample space), Turbo Roundabouts are ideally suited to handle the intersection requirements for provincial roadways – as they are the safest intersections for mid capacity. 72 4.1.4.1.1 Turbo Roundabout Definition Turbo Roundabouts are distinct forms of multilane roundabouts with four mandatory features [9]: 1. Entering traffic gives way (priority) to at least two circulating lanes on at least one branch of the roundabout (capacity limiter) 2. Entering traffic never gives way to more than two lanes of traffic (safety) 3. The circulating lanes are separated by raised curbs to prevent lane changing (safety) 4. Lanes spiral outward so drivers can maintain (low) speeds as they transition from entrance to exits, as a form of driver comfort (comfort) Two additional features may be present: 5. Main branch exits have two lanes, smaller side branches may have one lane exit lane (capacity) 6. Each segment of the roundabout has an option lane where drivers may choose to leave the roundabout or continue on (pre-selection) 73 Figure 32 - Basic Turbo Roundabout Figure 32 above depicts a spiral effect. While each radii is constant over a quadrant, connected together, they form a spiral due to differing origins. The spiral is called a ‘Turbo Block’ and is used in layout of a Turbo Roundabout’s geometry. 4.1.4.2 Turbo Roundabouts Constructed to Date The following map shown in Figure 33 was compiled by Dirk De Baan and shows the proliferation of Turbo Roundabouts after starting in the Netherlands. More information is available on his website [60]. 74 Figure 33 - Turbo Roundabouts Constructed within Europe to Date, Adapted From [60] 4.2 Methodology Initially, the author was not aware of a list of complete Turbo Roundabout sites that existed in the Netherlands; however one was found later; first attempts to discover sites to visit was based primarily on proximity and searching through orthographic maps via Google Maps for locations on nearby Provincial Highways. For a site to be selected to survey, it needed to meet the three main criteria: 1. Type - There are five main types of Turbo Roundabouts (Egg, Basic, Knee, Spiral, and Rotor), the goal was to survey at least one of each. 2. Proximity – Sites would primarily be visited by cycling from the City of Delft, or, from a train station if further away. 3. Accessibility – Sites would need to have the possibility for us to approach from a viewable location to assess the speed of vehicles using the roundabout, and perform unobstructed vehicle counts Turbo Roundabout Egg Roundabout Partial Roundabout Knee Roundabout Look-Alike Turbo Dogbone Roundabout Spiral Roundabout Oval with Turbo Features Turbo Traffic Circle Rotor Roundabout Star Roundabout Unknown Teardrop Other 75 4.2.1 Sites Visited Table 10 - Field Visits by Roundabout Type Site # Roundabout Type 1 4-Legged Knee Variant – Turbo Roundabout 2 4-Legged Basic Variant – Turbo Roundabout 3 4-Legged Egg Variant – Turbo Roundabout 4 3-Legged Stretched Knee Variant – Turbo Roundabout 5 4-Legged Rotor Variant – Turbo Roundabout 6 3-Legged Stretched Knee Variant – Turbo Roundabout 7 6-Legged Elongated Single Lane Roundabout As may be shown above in Table 10, only four TR variants were visited (Egg, Basic, Knee, and Rotor); the reason for this was due to lack of Spiral variants in proximity to Delft. Figure 34 - Map of Sites Visited Within the Netherlands 76 4.2.2 Province of South Holland Traffic Counts Weekday and Weekend Traffic Counts were requested from the Province of South Holland for all selected provincial highway survey locations. Unfortunately, the Province could only provide traffic volumes on provincial roadway sections on each side of selected survey locations – these values were used in conjunction to surveyed flow data (share of volume per leg) to interpolate anticipated peak volumes for the Turbo Roundabouts. The Turbo Roundabout Location, Type, Peak Hour Highway Leg Volumes, Projected Peak Hour Volume may be found in the location data that follows. Am to PM conversion factor was derived by comparing the AM to PM highway traffic volumes for legs attached to the Turbo Roundabout (from Provincially supplied data) and averaging the factors. 4.2.3 In Person Traffic Counts & Velocity Measure Once sites were selected, they were planned to allow for adequate travel time for arrival during peak traffic times (between 8 and 10 AM, or between 3 and 4:45 PM). Upon arrival, traffic counts were conducted, followed by speed counts. Excluding the first site, all sites’ approach legs were sampled for volume using five-minute counts; thirty vehicles each from the inner and outer lane were sampled for circulating velocity. The tool used for velocity was a phone app using manual tracking at a known distance; the author estimates there may be up to 10% discrepancy on vehicle speeds due to human error, however this should likely be controlled by the large amount of sampling, and consistency between sites on velocity. Anticipated daily traffic volumes were calculated using the surveyed count, and multiplying for a peak hour, then multiplying that volume by nine. 77 4.3 Location Data 4.3.1 Location 1 Date: Monday June 13, 2022 Time: 4:45 PM Weather: Sunny with clouds Location: 51.981455,4.447929 Type of TR: Knee – 4-Legged Special Features: Lane dividers incl Volume Counts (3 minute): L1: 32 L2: 50 L3: 18 L4: 51 Volume Split: L1: 21.2% L2: 33.1% L3: 11.9% L4: 33.8% Headway: L1: 5.6s L2: 3.6s L3: 10s L4: 3.5s Speeds: Outer Lane: 29.4 km/h Inner Lane: 25.1 km/h Signaling -Signaling on Entry to Inner Lane -Some signaling for right hand turn on entry only Comments: Platooning traffic on leg 4, sign masts 200m in advance of T.R for major approaches, but only 100m in advance for minor (slower) approaches Anticipated Daily Volume: L1: 5,760 L2: 9,000 L3: 3,240 L4: 9,180 Total: 27,180 veh/day L1 L2 L3 L4 My location, (typical) 78 4.3.2 Location 2 Date: Tuesday June 14, 2022 Time: 9:09 AM Weather: Sunny, slight overcast Location: 52.031856, 4.477055 Type of TR: Basic Turbo Roundabout, 4-Legged – 1 minor leg Special Features: Cycling junction underneath approach legs – increased height -Acoustical barriers to protect neighboring residential developments; barriers made of three 1cm beveled edge tempered glass Volume Counts (5 minute): L1: 8 L2: 54 L3: 63 L4: 30 Volume Split: L1: 5.2% L2: 34.8 L3: 19.4 L4: 40.6 Headway: L1: 37.5s L2: 5.6s L3: 4.8s L4: 10s Speeds: Outer Lane: 30.2 km/h Inner Lane: 26.6 km/h Signaling -Pavement seemed different - - less asphaltic binder content? Comments: -Acoustical barriers cut loudness of traffic by 5 dB (32% decrease) Anticipated Daily Volume: L1: 864 L2: 5,832 L3: 6,804 L4: 3,240 Total: 16,740 veh/day L1 L2 L3 L4 Acoustical barriers 79 4.3.3 Location 3 Date: Tuesday June 14, 2022 Time: 4:15 PM Weather: Sunny, Clear Location: 52.073821, 4.558866 Type of TR: Oval – 4-Legged Special Features: Lane dividers incl, at grade cyclist crossing at minor leg (very visible); sign in center of roundabout Volume Counts (5 minute): L1: 77 L2: 20 L3: 63 L4: 3 Volume Split: L1: 47.2% L2: 12.3% L3: 38.7% L4: 1.8% Headway: L1: 3.9s L2: 3.6s L3: 4.8s L4: 100s Speeds: Outer Lane: 30.5 km/h Inner Lane: 28.7 km/h Signaling -Signaling on Entry to Inner Lane -Some signaling for right hand turn on entry only Comments: -No central island landscaping -Lane signage ~170m behind intersection Anticipated Daily Volume: L1: 8,316 L2: 2,160 L3: 6,804 L4: 324 Total: 17,604 veh/day L1 L2 L3 L4 80 4.3.4 Location 4 Date: Wednesday June 15, 2022 Time: 8:45 AM Weather: Sunny with clouds Location: 52.005077, 4.418833 Type of TR: Knee – 3-Legged Special Features: Lane dividers incl, median included for through traffic, cycling underpass Volume Counts (5 minute): L1: 103 L2: 77 L3: 10 Volume Split: L1: 54.2% L2: 40.5% L3: 5.3% Headway: L1: 2.9s L2: 3.9s L3: 30s Speeds: Outer Lane: 32.5 km/h Inner Lane: 25.8 km/h Signaling -Common to see vehicles signaling right for intent on entering -Some signaled right for exit maneuver Comments: n/a Anticipated Daily Volume: L1: 11,124 L2: 8,316 L3: 1,080 Total: 20,520 veh/day L1 L3 L2 81 4.3.5 Location 5 Date: Wednesday June 15, 2022 Time: 3:45 PM Weather: Sunny with clouds Location: 51.719391, 5.345932 Type of TR: Turbo Rotor – 4-Legged Special Features: -Lane dividers incl, no ‘Frogs’ on entry for any direction -Shrubs planted in center at driver’s eye level -Catch Basins located within dividing curbs (each lane crowned) -Some lighting in central island Volume Counts (5 minute): L1: 74 L2: 35 L3: 46 L4: 133 Volume Split: L1: 25.7% L2: 12.2% L3: 16.0% L4: 46.2% Headway: L1: 4.1s L2: 8.6s L3:6.5s L4: 2.3s Speeds: n/a n/a Signaling -Same as previous Comments: -One near miss L4 (entering driver switched lane to avoid collision), one near miss on L3 due to uneducated driver, saw 3 cars on L4 wait 45s Anticipated Daily Volume: L1: 7,992 L2: 3,780 L3: 4,968 L4: 14,364 Total: 31,104 veh/day L1 L2 L3 L4 82 4.3.6 Location 6 Date: Thursday June 16, 2022 Time: 8:15 AM Weather: Sunny with clouds Location: 52.004313, 4.280206 Type of TR: Knee – 3-Legged Special Features: Lane dividers incl, frogs incl Volume Counts (5 minute): L1: 17 L2: 67 L3: 87 Volume Split: L1: 9.9% L2: 39.2% L3: 50.9% Headway: L1: 17.6s L2: 4.5s L3: 3.4s Speeds: Outer Lane: 38.3 km/h Inner Lane: 30.5 km/h Signaling -Same as previous Comments: Platooning traffic on leg 3 Anticipated Daily Volume: L1: 1,836 L2: 7,236 L3: 9,396 Total: 18,468 veh/day L1 L2 L3 83 4.3.7 Location 7 Date: Thursday June 16, 2022 Time: 2:00 PM Weather: Sunny Location: 52.072421, 4.275520 Type of TR: Elongated single lane roundabout Special Features: 5 Approaches, 6 exits Volume (5 minute): Volume Count Volume Split Headway Cars: L1: 24 L2: 12 L3: 9 L4: 20 L5: 0 L6: 12 Bikes: L1: 11 L2: 7 L3: 12 L4: 11 L5: 2 L6: 20 Cars: L1: 31.1% L2: 15.6% L3: 11.7% L4: 26.0% L5: 0% L6: 15.6% Bikes: L1: 17.5% L2: 11.1% L3: 19.0% L4: 17.5% L5: 3.2% L6: 31.7% Cars L1: 12.5s L2: 25s L3: 33.3s L4: 15s L5: n/a L6: 25s Bikes L1: 27.3s L2: 42.9s L3: 25s L4: 27.3s L5: 150s L6: 15s Speeds: Outer Lane: n/a Inner Lane: n/a Signaling -No signaling noticed Comments: Ped & bike crossing at center was well placed allowing queuing of traffic Anticipated Daily Volume Total: 8,316 veh/day; 6,804 cyclists/day L1 L2 L3 L4 L5 L6 84 4.3.8 Location 8 Date: Tuesday June 21, 2022 Time: 8:15 AM Weather: Sunny with clouds Location: 51.980918, 4.495268 Type of TR: Basic Turbo Roundabout – 4-Legged w/ slip Special Features: Lane dividers incl, slip lane on L3 to L4 Volume Counts (3 minute): L1:63 L2:50 L3: 25 L4: 29 Volume Split: L1: 37.7% L2: 29.9% L3: 15.0% L4: 17.4% Headway: L1: 4.8s L2: 6s L3: 12s L4: 10.3s Speeds: Outer Lane: 29.4 km/h Inner Lane: 24.6 km/h Signaling -same as previous Comments: -Bus stop on L4 Entry just off cycling path was convenient location -Federal HWY at elevation and TR served as collector intersection Anticipated Daily Volume: L1: 6,804 L2: 5,400 L3: 2,700 L4: 3,132 Total: 18,036 veh/day L1 L2 L3 L4 85 4.3.9 Provincial Comparison Data The Turbo Roundabout Location, Type, Peak Hour Highway Leg Volumes, Projected Peak Hour Volume may be found in Table 11, below. Am to PM conversion factor was derived by comparing the AM to PM highway traffic volumes for legs attached to the Turbo Roundabout (from Provincially supplied data) and averaging the factors. Project Peak Hour Turbo Roundabout Volume was found by taking the highway volumes and dividing by the volume share (as a percentage) of the highway legs; volume share of highway legs was found within the location data. 86 Table 11 - Provincial Data Comparison Table Location: Type: Peak Hour Highway Leg Volumes (from Province): Projected peak hour Turbo Roundabout volume (using location survey data): Surveyed Peak Hour Traffic Volume: 1 Knee – 4 Legged 984 (leg 2) + 1,248 (leg 4) = 2,232 (PM) 2,232 / (0.331+0.338) = 3,330 (PM) (32+50+18+51) * 20 = 3,020 (PM) 9% lower than provincial data 2 Basic Turbo Roundabout – 4 legged 978 (leg 2) + 1,193 (leg 4) = 2,171 (AM) AM to PM Conversion Factor = 1.215 2,171 / (0.348+0.406) = 2,879 (AM) AM to PM Conversion: 2,879 * 1.215 = 3,498 (PM) (8+54+63+30) * 12 = 1,860 (AM) 35% lower than provincial data 3 Oval – 4 Legged 693 (leg 1) + 1,043 (leg 3) = 1,736 (PM) 1,736 / (0.472+0.387) = 2,021 (PM) (77+20+63+3) * 12 = 1,956 (PM) 3% lower than provincial data 4 Knee – 3 Legged 706 (leg 2) + 1,342 (leg 3) = 2,048 (AM) AM to PM Conversion Factor = 1.331 2,048 / (0.542+0.405) = 2,161 (AM) AM to PM Conversion: 2,048 * 1.331 =2,726 (PM) (103+77+10) * 12 = 2,280 (AM) 6% higher than provincial data 5 Turbo Rotor – 4 legged No data available – outside Province of South Holland 3,456 (PM) 6 Knee – 3 Legged 1,076 (leg 2 – AM) AM to PM Conversion Factor = 1.078 1,076 / 0.392 = 2,745 (AM) AM to PM Conversion: 2,745 * 1.078 = 2,959 (PM) (17+67+87) * 12 = 2,052 (AM) 25% lower than provincial data 7 Dog Bone Roundabout No data available – roundabout operated by Den Haag 924 Cars, 756 Bikes 8 Basic Turbo Roundabout No data available 2,004 (AM) 87 4.4 Chapter Conclusion Overall, it appears that surveyed traffic data was typically within 16% of projected volumes. Traffic delay for all sites was typically very low (<30 seconds), and there were few near misses witnessed; near misses are catalogued within the location data in the previous subsection. Highest observed passenger car speed was 47km/hr; the next highest observation was 43 km/hr. There were at least 30 observations per lane to come up with average velocities. Tractor trailer speeds were typically 5-10km/hr slower than passenger vehicles. The Netherlands has appealing road features that permit active transportation that aren’t common in Canadian environments. Turbo Roundabouts seem to permit excellent road movements while promoting the safety aspects of a single lane roundabout (lower speeds, more control, better sightlines), without necessarily sacrificing capacity. 88 Chapter 5: Discussion This chapter will discuss findings, make conclusions, identify lessons learned, and recommend future research regarding Turbo-Roundabouts. The Kelowna case study feasibility design project, and European field visits have offered a unique opportunity to explore how Turbo Roundabouts operate, and how they may be applicable to Canada. 5.1 Upstream versus Downstream Control North American Roundabouts may be seen as using an ‘upstream’ control method for speed reduction as opposed to a ‘downstream’ control method used in the Netherlands. ‘Upstream’ is in reference to drivers needing to control their speed prior to entry into the single lane roundabout, upstream of the circulating lane’s entry; this is due to geometric constraints. The ‘downstream’ control is a geometric constraint placed upon entering the circulating lanes (found in the Netherlands) accomplished via raised lane dividers. While ‘upstream’ control is effective at single lane roundabouts, and may increase capacity, when an additional circulating lane is added to the outside of the roundabout, problems may emerge. This is mainly due to the tenets of what makes roundabouts safe (low speeds, yield on entry) being susceptible to violation; other problems created include elongated pedestrian crossings, poor sight lines, and weaving. 5.2 Safety Principles The second edition of FWHA’s “Roundabouts: An Informational Guide” highlights in the opening paragraph of the Safety chapter ‘feature changes’ that have an effect on collisions. Because the ‘upstream’ control method is used in North America for speed reduction, in combination with swept paths of larger design vehicles, all of the 89 engineered feature factors (with exception of angle between intersecting legs) are exacerbated in a North American multilane roundabout design as compared with the Dutch design method; this is shown in Table 12, below [1]. Further, lane markings in similar circumstances have been proven not to be effective at deterring traffic from taking the fastest / shortest path[13]. Table 12 - Engineering 'Feature Effects' Observed within Modern Roundabout Geometry [1] Two key principles that modern roundabout design relies on for safety (yield on entry, slow circulating speeds) are easily violated when multiple approach lanes are available, and no lane channelization is implemented. This leaves one to the questions: “Is this a problem, and how much of a problem is it”. To satisfy these questions, one may need to understand how and when severe collisions are occurring, to understand how to prevent them. It’s unclear if time (season or hour) and relative volume play a role in likelihood of collision type. While the modern multilane roundabout geometric issues may contribute to increased collision frequency, the severity of collisions may be isolated at off peak periods when drivers aren’t forced to be compliant with lane markings due to perceived traffic proximity and density. Regardless, this potential problem is eliminated with lane channelization. Feature ChangeEntering Circulating Entry Width Increase IncreaseEntering Circulating Central Island Diameter Increase IncreaseEntering Circulating Angle between intersecting legs Increase DecreaseExiting Circulating Inscribed Circle Diamter Increase IncreaseExiting Circulating Central Island Diamter Increase IncreaseExiting Circulating Circulating Width Increase IncreaseApproach Lane Width Increase IncreaseEngineering Feature Effects Observed within Modern Roundabout GeometryTraffic flow analyzedFeature Changes Collision Frequency Effect90 It should also be noted that while there are still fleet differences between the EU and North America, the design or average vehicle turning radii and mean speed differences aren’t significant for average passenger cars and most tractor trailers. There are concerns about lane use from a tractor trailer or long vehicle perspective, particularly in urban centers where lane changing between shortly spaced nodes may be challenging, however this would be problematic in any case, whether a traffic signal, multilane roundabout, or Turbo Roundabout was used. The NCHRP 672 manual is rife with objective safety principles about single lane roundabouts that are applicable to Turbo Roundabouts, but not to multilane roundabouts. A reader need only replace “single-lane” with “turbo”, and the sentences maintain congruency and validity with single lane principles and observed data, for example: “Therefore, the ability of single-lane Turbo roundabouts to reduce conflicts through physical, geometric features has been demonstrated to be more effective than reliance on driver obedience to traffic control devices”, as modified from page 5-7 of NCHRP 672. Further examples highlighting the equivalence of Turbo Roundabouts to satisfy single lane roundabout safety principles, modified from page 5-4 of NCHRP 672 are shown below:  “Turbo roundabouts have fewer vehicular conflict points in comparison to conventional intersections multilane roundabouts. The potential for high-severity conflicts, such as right angle and left-turn head-on crashes, is greatly reduced with Turbo roundabout use.”  “Low absolute speeds generally associated with Turbo roundabouts allow drivers more time to react to potential conflicts, also helping to improve the safety 91 performance of Turbo roundabouts. Low vehicle speeds help reduce crash severity, making fatalities and serious injuries uncommon at Turbo roundabouts.”  “Since most road users travel at similar speeds through Turbo roundabouts (i.e., have low relative speeds), crash severity can be reduced compared to some traditionally controlled intersections multilane roundabouts” Section 6.2.1 of NCHRP 672 states “The operating speed of a roundabout is widely recognized as one of its most important attributes in terms of safety performance”, and, “Although the frequency of crashes is most directly tied to volume, the severity of crashes is most directly tied to speed”. If the primary benefit of a roundabout is to increase safety over intersections, would it not be prudent to design multilane roundabouts that constrained excessive speed? Beyond this, it’s not likely to maintain consistent speed through a multilane roundabout as there are multiple significant radii changes, especially if performing lane changing. Lane changes and multiple driver operations within the circulating lanes increase driver workload. This is not ideal, especially considering the higher amount of conflict points within multilane roundabouts as compared to Turbo Roundabouts. Finally, when paired with grade separation these intersections can greatly increase active transportation participation by making vulnerable road users feel safer, which increases transport equity. Because of a more radial approach with Turbo Roundabouts, it is more tenable to consider tunnels or overpasses to cross these intersections’ approaches; the overall roadway width is narrower for approaches with Turbo Roundabouts, which reduces tunneling or overpass costs, as compared with multilane roundabouts. 92 5.3 Stewardship, the role of Government, and Safety One of the key differences between design implementation within the Netherlands and Canada is the use of public employees and a team of engineers tasked with upholding public safety; the Netherlands employees engineers for their preliminary design and stewardship of provincial and national highways, while Canada often contracts this duty out to private consultants. There’s an onus on public servants to continuously improve designs when they’re actively returning to them for collision investigations. North American design consultants don’t necessarily have the expertise or mentorship in-house to provide the same expertise, and in turn, quality of design product that may be required or created by a provincial or federal employee who is trained and familiar with this work; the main reason why stewardship is ideal for the public is because there is accountability and expertise for the entire asset lifecycle placed with the asset owner’s personnel. Without immediacy to a roadway’s performance once it begins operation, designers may be ignorant of potential learning opportunities; likewise, personnel operating roadways in North America may not require an engineering background, and in turn, proactive information to improve roadways may be siloed between asset owners and designers. While engineers are required to uphold the public safety, if engineers aren’t put in positions of stewardship it can systemically slow down the improvement of a road network. Finally, these mid sized intersections present an opportunity to owners (and users) to reduce intersection operating costs. There is a reduced power requirement as 93 no signals are needed, and there are no calibration or re-timing requirements as a result – in other words, TRs are resilient in power outages and self-adjusting to traffic demand. 5.4 Intelligent Vehicles It’s questionable whether Turbo Roundabouts could remain relevant with increased utilization of semi-autonomous and fully autonomous vehicles. Autonomous vehicles are widely understood to vastly outperform human drivers to significantly reduce (and nearly eliminate) collisions. While there have been limited studies on the increase in capacity of Turbo Roundabouts that have ‘smart’ vehicles driving upon them, initial reports suggest that >35% capacity increase may be expected [33]. Turbo Roundabouts still maintain the safety benefits for drivers without autonomous vehicles, a reduced footprint, emissions, and operations cost, while providing a significant capacity upside looking into the future. 5.5 Ethical Quandaries One observation made during research was the slow adoption of roundabout design practices in North America; this began with modern single lane roundabout design and continues today with multilane variants. In British Columbia, Professional Engineers are required ethically to hold paramount the safety, health, and welfare of the public, and to practice only in those fields where training and ability make the registrant professionally competent[61]. This language is common within the professional governance of other provinces in Canada. It would be difficult to seal innovative designs that you are professionally liable for if you: a) Are not trained by someone who is an expert b) Could lose your license to practice if you did 94 Design manuals are often written after ‘guinea pig’ designs constructed prove valuable and finding lessons learned; without ‘test subjects’, there would likely never be innovation in transportation. These novel (successful) designs often determine best practices and start the process of creating ‘design guidance’. Ironically with transportation engineering, it can be haphazardly to innovate something to improve public health, without exposing yourself to practicing outside your expertise. When transportation corridors are reviewed or planned, they’re usually subject to planning level economic analysis to determine potential costs and benefits of various transportation infrastructure schemes. The results of these reports (and recommendations) are provided to decision makers in order to make informed decisions with public capital regarding infrastructure asset management. These analyses are predicated on information from existing infrastructure that has been studied (collision rates, capacity, travel time, etc.) to forecast economic benefit. Without built Turbo Roundabouts, they can’t be forecast for economic performance; if something can’t be forecast, it won’t be recommended or designed. Without North American planning level resources available, it is difficult to predict how Turbo Roundabouts may perform in Canada. Without being recommended, novel intersection designs won’t be designed or constructed. Without design aides available in North America for Turbo Roundabouts, it’s very difficult for engineers to ethically go about designing a novel intersection type; this is somewhat of a circular problem. 95 Chapter 6: Conclusions 6.1 Kelowna Case Study Conclusions While it did not perform at LOS A in peak hours, and despite requiring specific lane constraints, the Kelowna Turbo Roundabout designed as part of this research demonstrated significant potential for social, economic, and environmental benefits compared to the existing signalized intersection. The TR travel delays were much shorter, the footprint fit the constrained land use (urban) scenarios compared to its traditional North American MLR cousin, and safety benefits from initial studies appeared significant. This intersection could also remove barriers for active transportation. With an aging population, and an onus on greener solutions for traffic moving into the future, Turbo Roundabouts are an ideal candidate in certain scenarios to reduce cost burden for road owners, reduce delay for drivers, increase safety for all road users, and reduce greenhouse gas emissions. It’s clear from the anticipated cost savings of predicted ICBC claims, and emissions / travel time savings, that this type of intersection would have long lasting present value benefits to the City and Province’s stakeholders. What isn’t clear, from a municipal perspective, are the trade-offs that would be required to justify the added expenditure of retrofitting the existing signalized intersection with this TR, including its MUP tunneling or overhead bridges. It’s estimated the cost increase of tunneling versus bridges would be in the $2 – 4-million-dollar range, however long-term benefits of having tunnels may be justified if it promotes more use in active transportation. Although it may seem expensive for an initial cost, the City has made its goals very clear 96 regarding promoting safety, active transportation, and climate action, particularly in the area of this intersection. 6.2 Europe Field Visits Conclusions The road network policy within the Netherlands provides distinction between ‘grey roads’, ‘through roads’, and ‘local roads’ and has consequentially allowed road safety to excel. By limiting through movements in city sectors (local roads) and forcing vehicles back onto through roads, local traffic is significantly protected. By providing more grade separated and priority crossings to cyclists and pedestrians on through roads and local roads, respectively, active transportation barriers are significantly reduced. Acoustical controls for Turbo Roundabouts were relatively common in areas within a few hundred meters proximity to residential zones. These controls were typically five-meter-high panes of glass, structurally supported, at angles that directed reverberating sound up into the sky; the glass would surround these intersections, with exception to approaches, and typically have multiple panes with an air gap between them. The glass was tempered, purposely cracked (so visible to birds) but not opaque, and shatterproof. The idea of using shatterproof cracked glass, as opposed to a fence or other opaque structure makes sense in the application of sound barriers, as it permits visibility while also reducing noise significantly. Average circulating speeds were slightly slower than North American roundabouts; near misses witnessed were less potentially severe. Tractor trailers had very little issue maintaining adequate speed in low volume circumstances. The observed volumes indicated slower circulating speeds of the Turbo Roundabout didn’t 97 negatively affect their capacity as much as might be expected. It seemed that drivers took smaller gaps in traffic and utilized the inner lane more than typical North American multilane roundabouts; This ‘smaller gaps’ theory has been postulated by Dr. Bertus Fortuijn in his capacity analysis of Turbo Roundabouts[62]. Grade separation for Turbo Roundabouts seems like an appropriate method of control in or near more urban applications due to the sheer traffic at approaches with more than two lanes of entry; Grade separation was the standard method of pedestrian and cyclist control where more than one lane on an approach existed. This was seemingly economic in the Netherlands due mainly to the sheer amount of public transportation options available (i.e., high cycling volumes, comparable to vehicle volumes in many cases), ease of use for the network for cyclists and pedestrians, and values on safety and accessibility. 6.3 North America Trends Turbo Roundabouts are becoming a more curious item among roundabout professionals in North America. Within Jacksonville University, Florida, USA,, one has been constructed and looks promising[63]. Another has been constructed at the intersection of two state highways in California, and has so far shown ‘mixed results’[64]. Neither roundabout seems to have altered overall Turbo Roundabout geometry dimensions (or engineered features) used in the Netherlands, other than diameter, despite having different fleet vehicles; there is still zero guidance for application of Turbo Roundabouts in North America, yet they are being designed and built. 98 6.4 Contributions of the Thesis This research determined that Turbo Roundabouts are very applicable to Canada, and have significant potential social, environmental, travel time, and safety benefits; the research also determined barriers exist to their design and implementation. A few modifications to the Dutch style Turbo Roundabout would be required to accommodate North American Design Vehicles, particularly:  Lane Divider Width  Entry Radii  Circulating Radii Snowplows and snow removal equipment were not found to be a barrier to Turbo Roundabout implementation, contrary to common perception. Designing to accommodate plowing equipment is completely reasonable from a geometric and operational perspective, however this is a knowledge gap. Throughout scrutiny of economic analysis and feasibility design, the aforementioned gaps in translating the design and planning guidelines from the Netherlands to North America were identified; it was found that Turbo Roundabouts would be very beneficial from a lifecycle perspective. Many of the planning and design gaps discovered through this research ranged due to the physical fleet differences of vehicles, the environmental differences of the countries, or the policy differences in traffic. These gaps may not have been recognized without the exercise in design, economic analysis, or field visits to the Netherlands. Many of the contributions are lessons learned, and although not resolved within this thesis, they are identified for future research. 99 6.5 Lessons Learned and Future Research Opportunities The Roundabouts – Application and Design manual from The Netherlands seems to recommend a splitter island of 7 metres in width for Turbo Roundabouts. This hasn’t been accommodated in Kelowna’s intersection retrofit TR design rendition, which had a splitter island of 4 metre width (minimum recommended splitter width for Turbo Roundabouts) to reflect RoW constraints. There is an opportunity to remove some MUP’s along one side of some approaches while still maintaining adequate pathways (in each direction) for active transportation; ease of crossing the intersection would likely not cause issue if only including MUP’s on one side of certain approaches. Having extra width within the ROW would allow for wider splitter islands, and probably allow higher traffic capacity, with larger room for error between conflicting vehicles. This would likely result in a safer intersection for automobiles, without affecting pedestrian and cyclist convenience too adversely. Tunnel (or bridge) requirements could also be reduced to three crossings, instead of four, to reduce construction cost & timeframe. An alternative to specific lane use requirements (regarding heavy vehicles) is needed to address the ‘WB-21 problem’. A wider lane divider could be proposed in a Canadian context to address lane over-tracking, which would prevent excessively wide lanes, while also permitting appropriate speeds, and simultaneous use of multiple circulating lanes. Further, it’s unclear how much of a potential challenge lane dividers may pose to snow clearing activities. Initial conversations with City of Kelowna managers and snowplow drivers suggest it would NOT be an issue. Moreover, it’s 100 arguable that lane dividers could be used for snow storage, as long as sightlines weren’t compromised. More research is required in this area. Another future research topic is that more information is required to provide better formulae to North American TR applications representing fastest path or anticipated speeds (performance checks) of different variants of roundabouts. Currently it appears the design standards of North America supports use of formulae borrowed from the American Association of State Highway and Transportation Officials’ Policy on Geometric Design of Highways and Streets (AASHTO ‘Green Book’)[65] and applied towards roundabouts – as per the Kansas State Roundabout Design Manual. It’s unclear if the use of highway data for single curve speed anticipation is appropriate for compound spiral curve maneuvers present in Turbo Roundabout applications, or roundabout applications. We would like to seek more information surrounding rationale for this formula’s use, knowing the actual anticipated speed of each lane is of paramount importance for safe design of these intersections. The Dutch Formulae seems to rely on conservation of momentum to justify the driver behavior, which seems more logical and closer to observed behavior in our Dutch field research. Network analysis of the Kelowna Turbo Roundabout at the location shown in Chapter 3 would be beneficial. Identifying if timing changes to the surrounding signals could significantly improve the level of service at the proposed roundabout would help. While initial results of the Sidra analysis were promising for the applicability of Turbo Roundabouts for larger capacity intersections, the software had limited applicability. If use of the intersection were predicated on specific lane use, further research at this intersection would be warranted using microsimulation software such as VISSIM to 101 better reflect the specific arrival patterns of traffic in this context. This type of analysis would likely be valuable at most potential intersection locations with a feasibility level intersection geometric model to determine more accurate and realistic traffic operations, level of service, and relative externalities. Travel time costs in this study were limited to what is prescribed by the Province of British Columbia through their document “Default Values for Benefit Cost Analysis in British Columbia”. Due to age of this guide, and lack of unifying agreed understanding on the expected economic impacts of excessive travel time, further investigation into appropriate values to utilize for travel time are likely warranted. Better understanding of relative cost to society for travel time impacts would better underscore the relative benefits of any intersections proposed, not just Turbo Roundabouts, regardless of proposed project location. These planning level limitations exist from provincial level through to the existing Canadian Roundabout Design Guide, and likely prevent an accountable representation of the potential (unrecognized) economic, social and environmental benefits of roundabouts in comparison to traditional intersections. Seeking approval from the Province of South Holland’s Highways Division, prior to hiking near remote video monitored intersections, is advisable to researchers seeking to survey these types of intersections. Two lessons were gleamed from interviewing the inventor of the Turbo Roundabout at their home: 1. Lane saturation expectations could be reduced from 0.8 to 0.65 for adapting the Dutch planning level models to North American applications as a 102 precautionary tool to aid with feasibility assessment, prior to having many Turbo Roundabouts actually constructed and verified models. 2. Lane metering only helps increase capacity when there are two lanes to cross for entering traffic, because lane metering only increases circulating lane utilization, which will only be low on inside lanes[66] The Dutch don’t have snow that sticks year-round. It’s still questionable if snowplow operators would be comfortable clearing snow from a Turbo Roundabout. Proposed geometric alterations to the typical Dutch Turbo Roundabout would be required to reflect North American fleet vehicles. Research is still required to determine if Snowplows can navigate any proposed lane geometry. As rear ending is the most common type of collision for multi lane roundabout, it would be ideal to determine where this is occurring (upon approach versus circulating or exiting). If on approach, it may be due to driver attention shift towards the circulating lane, as opposed to in front of their vehicle. If so, it is a strong argument for Turbo Roundabouts, especially as improved sight lines may reduce or lower this risk. Another unknown regarding the potential magnitude of all variants of Turbo Roundabouts is the relative understanding of greenhouse gas emissions at intersections. There is limited research available to underpin the forecast amount of emissions, as a portion of average trips, that intersection emissions are responsible for. It is generally recognized that most road network delays occur at intersections, so it is reasonable to assume most emission occur at intersections, but quantifying these relative amounts would help. There is also limited research to understand what percent of intersections that Turbo Roundabouts could be applicable for in Canada, and so a 103 screening ‘checklist’ of criteria would be a good ‘next step’ toward that research and planning for Canadian transportation planners and engineers. Understanding potential for greenhouse gas reduction amounts for utilizing more of these intersections into the future may help produce planning level tools to understand how to effectively reduce greenhouse gas emissions on transportation, and how effective overall within the transportation network these intersections may be considered at the planning stage. 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Juniper, “Lambertus Fortuijn Interview - June 17, 2022,” 2022. 113 Appendices Appendix A Sidra Turbo Roundabout Parameters 114 Appendix B WB-21 Information Used with permission 115 Used with permission 116 Used with permission 117 Appendix C Sidra Reports for Feasibility Design 118 119 120 121 122 123 124 125 126 127 128 129 Appendix D Preliminary Case Study Design Drawings 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 Appendix E Preliminary Case Study Construction Cost Estimate 145 146 147 148 149 150 Appendix F Preliminary Case Study Capital Cost Estimate
Thesis/Dissertation
eng
Civil Engineering
Vancouver : University of British Columbia Library
Attribution-NonCommercial-ShareAlike 4.0 International
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Lovegrove, G. R.
Sustainable transport safety : are turbo roundabouts applicable to Canada?
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