Subcontract: NCHRP 15-73 Design Options to Reduce Turning Motor Vehicle – Bicycle Conflicts at Controlled Intersections

Christopher Monsere, Portland State University



One of the most common locations for fatal motor vehicle-bicyclist crashes is at intersections, which inherently have a large number of turning conflicts. Reducing these conflicts is a key objective in improving intersection safety across all modes. Of particular concern for bicyclists’ safety at intersections are the conflicts between straight-through bicyclists and motor vehicle right-turns and opposing left-turns. Despite the widespread acknowledgement of this problem, transportation engineers and planners still lack definitive guidance on how to safely and effectively design for bicyclists at intersections in the United States.

Design practices that drop bicycle pavement markings and signs at intersections, providing no positioning guidance for motorists or bicyclists, can lead to confusion over who has the right-of-way through the intersection. Some jurisdictions continue bicycle lane markings all the way through intersections; in others, the lanes are dashed. Moreover, the use of a variety of innovative treatments including bike boxes, use of color, bicycle signals, and separated crossings is increasing across the country; while some of these have been examined through research studies, with some promising results, the results are inconclusive.  Research is needed to identify design best practices to reduce conflicts at intersections.
The objective of this research is to develop guidance and tools for transportation practitioners to use to reduce turning conflicts between motor vehicles and bicycles at controlled intersections. 

Project Details

Project Type:
Project Status:
In Progress
End Date:
October 02,2023
UTC Grant Cycle:
non-UTC project