Signal phasing strategies are a core tool for better intersection design. This section provides signal phasing options for protected and dedicated bike intersections, with an emphasis on mitigating conflicts between motor vehicle and bicycle movements. It supplements, and in some cases updates, the NACTO Urban Bikeway Design Guide’s recommendations for bicycle signals. The following phasing options reflect the recent experience of North American cities and should be adapted to local standards and practices.
Trade-offs between comfort and convenience are present in all signal operations. Motor vehicle turning movements consume a large amount of time and space at intersections. At the same time, many riders express a comfort preference for protected bicycle signal phases, with fully separate motor vehicle turn phases. However, in some cases, fully separated phases may result in longer wait times for both bike and automobile travel, reducing perceived convenience.
Setting signal progressions to bike-friendly speeds can reduce bicycle delay caused by a separate turn movement, while supporting bus transit reliability and disincentivizing speeding. At some intersections, it is more effective to provide flexibility to people walking and biking, allowing them to proceed even after motor vehicles begin to turn across the bikeway. This operation is represented by leading bike intervals and protected-permissive bike signals.
The relative risks and efficiencies among these options are important considerations for the practitioner. Intersection and corridor signal timing analysis, the existing risks and issues at an intersection, and an understanding of how people using the street will respond to signals are all important factors in bike intersection operations decisions.