Roundabouts and Bikes: Like Oil and Water or Peanut Butter and Bananas?

Transcription

1 Roundabouts and Bikes: Like Oil and Water or Peanut Butter and Bananas? 2017 APBP PDS Conference Memphis, Tennessee Alek Pochowski, AICP, PE Darren Buck June 27, 2017

2 Columbus Circle, New York City

3 In America, Traffic Circles Got Bigger Before Falling out of Favor in the 1950s

4 Meanwhile, England Developed Off- Side Priority

5 In the early 1990s, Roundabouts Arrived in America

6 History of Roundabouts in North America

7 Traffic Circle Family Rotaries Traffic Calming Circles Roundabouts Engineered Traffic Circles Traffic Circles

8 Rotary vs. Roundabout 8

9 Early Roundabout Opportunities» Lower speeds and fewer conflict points result in less crashes» Crash severity is significantly reduced» Traffic operations are improved, especially outside the peak hour» Provides aesthetic and gateway treatment opportunities» Usually requires more right-of-way at the intersection, but much less right-of-way on the approaches

10 Early Roundabout Issues» Size (predominantly too small)» Splitter Islands (too short)» Design Vehicles (not accommodated)» Bicycles and Pedestrians (not fully accommodated)» Too much sight distance» Path Alignment (not understood at multilane roundabouts)» Multilane roundabout striping (concentric or non-existent)» Built for the design year (resulted in much higher crash rates than expected)

11 Recent Roundabout Lessons Learned» Phased design (build for future expansion to the inside)» Accessible pedestrian crossings» Long splitter islands (150 to 200 ft)» Consider design vehicle needs (typically the largest vehicles don t need to make all turning movements)» Provide separation between large vehicles, bicycles, and pedestrians

12 Roundabouts Come to the City» More users and activity than typically found in suburban/rural counterparts» Typically constrained» Necessitates tradeoffs Benefits Decreases vehicle speeds Enhances safety for pedestrians Provides aesthetic opportunities May improve access management May reduce delay and emissions Considerations Accessibility for visually impaired pedestrians Right-of-way needs Type of vehicle used for the design (emergency vehicles, trucks, buses) Parking Interaction with adjacent traffic control devices Sight distance

13 Who s Riding Bikes, and What s Stopping Them?» Almost 70% of people are interested in riding a bike» Only 13% of people feel confident and comfortable riding their bikes to get around, under current conditions» The largest user group (interested but concerned) prefers greater levels of protection and separation, especially on higher speed and higher volume streets Source: Jennifer Dill and Nathan McNeil. Four Types of Cyclists? Testing a Typology to Better Understand Bicycling Behavior and Potential. Portland State University OTREC. August 2012.

14 Protected Intersections Sidewalk Level Cycle Track Recent Industry-Wide Bicycle Practice

15 Intersection Bicycle Design Principles Roundabouts are compatible with all of these principles!»provide space for bicyclists»reduce conflict points»maximize bicyclist visibility»reduce speed differential»provide predictable and direct navigation»minimize stop-start maneuvers

16 Bend-In Bend-Out Treating Bikes at Intersections

17 Protected Intersections Credit: Nels Nelson

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19 1976 FHWA Safety and Location Criteria for Bicycle Facilities

20 Dutch CROW Manual

21 As a vehicle in the circulatory roadway In a bike lane in the circulatory roadway With pedestrians in a shareduse path Separate from pedestrians in a separated bike lane Grade separated Bicycle Options at Roundabouts (Least to Most Protection)

22 As a Vehicle in the Circulatory Roadway» This is always an option, but becomes less attractive as roundabouts become more complex» This should not be the only bicycle accommodation at a multi-lane roundabout

23 Bicycles and Roundabouts: Current Practice» Low-volume: encourage bicycles to circulate with vehicles» High-volume: provide separate bicycle path with bike ramps» Give bicyclists option of either being vehicle or pedestrian First Protected Intersections in the United States!?

24 Wisconsin Department of Transportation Facilities Development Manual Bicycles and Roundabouts: Current Practice

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26 Bicycle Lanes in the Roundabout MUTCD 9C.04 Markings for Bicycle Lanes: Standard: Bicycle lanes shall not be provided on the circular roadway of a roundabout (Image mirrored for right-hand driving)

27 Bicycle Lanes in the Traffic Circle

28 Bicycle Lanes in the Roundabout

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30 MassDOT Separated Bike Lane Planning and Design Guide

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33 Inman Square»Known bicycle and pedestrian safety concerns at Inman Square»Boston Cyclists Union engaged KAI to evaluate a roundabout option»kai and Boston Cyclists Union coordinated with the City of Cambridge

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36 Design Priorities Priority» Identify a reasonable roundabout concept that provides a safe environment for pedestrians and bicyclists Other Considerations» Operates acceptably and minimizes queueing» Avoids impacts to the Mayor Alfred E. Vellucci Community Plaza» Considers access to and from the Inman Square Fire House» Allows buses to go east-west/west-east on Cambridge Street and Hampshire Street, along with north-east/east-north on Springfield Street and Hampshire Street» Allows WB-50 design vehicles to travel east-west /west-east on Cambridge Street and Hampshire Street

37 High-Level Roundabout Operations Analysis An analysis of the existing configuration and other alternatives was not completed by KAI Based on observed existing queue lengths, roundabout operations appear to be an improvement over existing conditions

38 Initial Design

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40 Charrette

41 Revised Design

42 Bertus Fortujin Two-Way Cycle Track

43 Grade-Separated

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45 The District s One Roundabout

46 Neighborhood Traffic Calming Circles»Planning to implement more as part of planned bike boulevards

47 Thomas Circle»Signalized with outer bike lanes

48 Washington Circle

49 Grant Circle (Temporary Configuration)

50 Grant Circle Adapted from: All Walks

51 Grant Circle (Proposed Ultimate Configuration)

52 Sherman Circle (Proposed Ultimate Configuration)

53 Summary»Just like peanut butter and bananas, roundabouts and bikes are compatible»design for all cyclists, not just those currently using the facility»bicycle facilities through the roundabout should be designed at similar stress levels as facilities on the approaches»innovation and creativity are great! Just make sure the design follows the principles of roundabout and bicycle design.

54 Thank you. Alek Pochowski, AICP, PE Darren Buck