Simulating and assessing the effect of a protected intersection design for bicyclists on traffic operational performance and safety

Abstract

The focus of this research is to simulate and assess the effect of a protected intersection design (PID) for bicyclists on traffic operational performance and safety. The PID was modelled and evaluated at the intersection of Tyvola Rd and South Blvd in Charlotte, North Carolina, USA. Traffic was modelled considering the existing intersection design and proposed PID using Vissim microscopic traffic simulation software under conditions of 0% bicycles to 15% bicycles. Safety was then analysed using Surrogate Safety Assessment Model (SSAM), and conflicts were defined as a 1.5-second intersection of two or more trajectories. There is no conclusive evidence that PID negatively effects operational performance (vehicle delay and level of service) at the selected study intersection. The type and total number of bicycle-related conflicts per bicycle varied with the percentage of bicycles. As much as an 80% reduction in the total number of bicycle-related conflicts could be observed if the percentage of bicycles exceed 10%. Benefits due to the implementation of PID could be greater at intersections with high bicycling activities. The findings support the hypothesis that the PID reduces the number of conflicts, and therefore improves safety.

Keywords

• Protected intersection design
• Bicyclist
• Delay
• Vissim
• Conflict
• SSAM