Evaluation of Level of Service and Safety for Vehicles and Cyclists at Signalized Intersections

Delay, or level of service (LOS), and road safety are two of the main factors considered when designing traffic control. Urban cycling has been growing in recent years as an efficient, healthy, and inexpensive transportation mode. Cities are seeking strategies to enhance comfort and safety for commuting cyclists, particularly on high-demand urban corridors. The purpose of this study is to evaluate the impact of different traffic signal designs at intersections with bicycle facilities. Three strategies are evaluated and compared to the base case (BC) scenario: a partially protected (PP) design, a completely protected (CP) design, and a completely protected with protected turn phase (CPT). These strategies were simulated across four intersection designs and 156 combinations of cyclist and vehicle flow to obtain LOS and safety provided to crossing cyclists using conflicts measured by post-encroachment time. Vehicle delay was evaluated using VISSIM microsimulation software, while conflicts were measured using the Surrogate Safety Assessment Model (SSAM) developed by the Federal Highway Administration (FHWA). The simulation results showed that the CP phase provides the highest level of safety for all four intersections, though it also yields the worst LOS. Although the PP design was not the superior considering any one metric, it shared approximately the same LOS compared to the BC while reducing the number of crossing conflicts by as much as 50%. Future work will validate the actual performance of several intersections within the city of Montreal with video data to evaluate vehicular delay and post encroachment time (PET) crossing conflicts.

• Supplemental Notes:
  • This paper was sponsored by TRB committee ANF20 Standing Committee on Bicycle Transportation.
• Authors:
  • Ledezma-Navarro, Bismarck
  • Stipancic, Joshua
  • Andreoli, Anthony
  • Miranda-Moreno, Luis
• Conference:
  • Transportation Research Board 97th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2018-1-7 to 2018-1-11
• Date: 2018

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 16p

Subject/Index Terms

• TRT Terms: Cyclists; Drivers; Exclusive phasing; Level of service; Signalized intersections; Simulation; Traffic conflicts; Traffic delays; Traffic flow; Traffic safety; Traffic signals; Vehicle mix
• Subject Areas: Highways; Operations and Traffic Management; Pedestrians and Bicyclists; Planning and Forecasting; Safety and Human Factors;

Filing Info

• Accession Number: 01657518
• Record Type: Publication
• Report/Paper Numbers: 18-04807
• Files: TRIS, TRB, ATRI
• Created Date: Jan 24 2018 9:25AM