1 Pedestrian and Bicycle Safety at Alternative Intersections and Interchanges Bastian Schroeder, PhD, PE ITE Mid-Colonial District Annual Conference April 16, 2018
2 Guide for Pedestrian and Bicycle Safety at Alternative Intersections and Interchanges
3 Inventory Summary A total of 1,686 AI&Is reviewed 48 signalized RCUTs 95 unsignalized RCUTS 1,378 MUTs 12 QRs 57 CFIs 96 DDIs Across 33 states Includes 17 international AI&Is
4 Standard Accommodations
5 Multimodal Benefits of AI&Is Potentially reduced pedestrian-vehicle conflict points Often feature two-phase traffic signal control with reduced pedestrian wait time Minimized crossing distances Simplification of conflicts to one-directional vehicular traffic May feature reduced turn lanes and permissive turns May provide opportunities for separated paths
6 Potential Challenges for Multimodal Users at AI&Is Potential for altered travel paths and pedestrian travel in unexpected locations Traffic approaching from unexpected directions Unfamiliar signal phases Uncontrolled crossing of turn lanes
7 Consider pedestrians and bicycles in initial design and throughout design process! Avoid need to retrofit by better initial placement of pole and/or walkway Source: ITRE Available right-of-way in island would have allowed for straightline crosswalk and walkway directing peds towards crossing Source: ITRE
8 Performance-Based Design Process Identify intended outcomes Establish geometric design decisions Evaluate performance outcomes Refine decisions based on performance Assess financial feasibility Select project or alternatives NCHRP Report 785 Performance-Based Design Process
9 From principles to method Guiding Principles Assessment Framework Performance- Based Criteria
10 Performance-Based Criteria 1. Traversing: traveling through the A.I.I. (does not include street crossings) Source: Kittelson
11 Performance-Based Criteria 2. Wayfinding: orienting to the A.I.I. geometry and understanding how to navigate
12 Performance-Based Criteria 3. Crossing: traveling across a street where conflicts with automobiles are possible Source: ITRE Source: Bastian Schroeder
13 Performance Criteria Overview Minimize Speed Differential / Control Speeds Minimize Travel Time Comfort and Quality of Service Provide and Convey a Reasonable Path Minimize/Manage Conflict Points Manage Lines of Sight and Visibility Provide Accessible Features
14 Minimize Speed Differential/Control Speeds Source: Google Source: Google
15 Minimize Travel Time
16 Comfort and Quality of Service Source: ITRE Source: ITRE
17 Provide and Convey a Reasonable Path
18 Minimize/Manage Conflict Points 8 Conflict Points 2 free/flow or accelerating 6 stopped or decelerating 8 Conflict Points 4 free/flow or accelerating 4 stopped or decelerating
19 Manage Line of Sight and Visibility Limited visibility: driver pedestrian & pedestrian driver Source: Source: GoogleFHWA
20 Provide Accessible Features Source: Google Source: Google
21 Next Steps Develop visualizations of unbuilt AI&Is covering broad range of design features/options Conduct four focus groups and on-line survey Participants are all from areas where a particular AI&Is are prevalent Non-engineer pedestrian/bicyclists Web-survey with focus group materials to allow a broad audience to comment on the proposed solutions
Sample Draft Visualization 22
23 Bastian Schroeder, PhD, PE bschroeder@kittelson.com