Investigating factors that affect conflicts between bicyclists and right turning vehicles at signalized intersections




bicyclists, cross-sectional regression models, intersection safety, right hook conflicts, safety countermeasures, surrogate measures of safety


Due to the recognition of active transportation as a beneficial alternative to more traditional modes of transportation, there is increasing interest in designing infrastructure systems to promote the safe use of forms such as bicycling. Collision data, which are typically used in road safety studies, may be incomplete and the use of such data is reactive as it requires collisions to have already taken place. Additionally, collisions involving bicyclists and vehicles are less common than those between vehicles. As a result, alternative approaches for evaluating the safety effect of various infrastructure attributes, such as the use of surrogate safety measures, specifically traffic conflicts, could be considered. Most collisions between bicyclists and vehicles occur at intersections and of these, collisions between right turning vehicles and bicyclists form the majority. The main objective of this study was to use cross-sectional regression models to investigate various intersection characteristics, including geometry, signal phasing, and bicycle infrastructure, with a view to determining which attributes are associated with a significant effect on right turning conflicts and how this may vary with different conflict severity levels. Using data for 65 signalized intersection approaches across Canada, various intersection attributes were found to be associated with the frequency of right turning conflicts such as exposure levels, the lateral offset of the bicycle facility and the grade of the approach to the intersection. The significance levels of the associated effects of certain attributes were observed to change with the severity level of the conflicts.


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Author Biographies

Robert Mansell, Toronto Metropolitan University, Canada

Robert Mansell is a Ph.D. candidate in Transportation engineering at Toronto Metropolitan University (formerly Ryerson University). His research interest is road safety analysis with a focus on vulnerable road users. Other research interests include evaluating both average and heterogeneous road safety treatment effects and exploring the use of causal machine learning.

CRediT contribution: Conceptualization, Data curation, Formal analysis, Writing—original draft.

Bhagwant Persaud, Toronto Metropolitan University, Canada


Bhagwant Persaud is a professor of Civil Engineering at Toronto Metropolitan University. His main research work has been in modeling the relationship between safety and highway characteristics, and in the application of these models in crash and noncrash based safety evaluation methodology. His research has resulted in a substantial number of peer-reviewed papers. He was a member of the Transportation Research Board Task Force for the Development of a Highway Safety Manual (HSM) and has worked on several research projects that developed content for the first and the forthcoming second editions of the HSM. He is an Associate Editor of Transportation Research Record, Journal of the Transportation Research Board.

CRediT contribution: Conceptualization, Supervision, Writing—review & editing.

Craig Milligan, Miovision Technologies Incorporated (formerly MicroTraffic), Canada


Dr. Craig Milligan is a recognized international expert in road safety engineering and product manager for safety technologies at Miovision. He has completed more than 600 in-service road safety reviews and design audits at all stages for more than $8B of capital projects, and he is a frequent road safety instructor for the International Road Federation. He built and led MicroTraffic, a leading road safety video analytics company, until its acquisition by Miovision in February 2023. He has authored over 30 technical papers and 10 design guidelines.

CRediT contribution: Data curation, Writing—review & editing.

Amanda Pushka, Miovision Technologies Incorporated (formerly MicroTraffic), Canada

Amanda Pushka is a Road Safety Engineer and certified Road Safety Professional. She holds her M.Sc. in Transportation Engineering from the University of Manitoba. She has experience completing road safety audits and collision analyses at locations across North America and New Zealand, assisting in planning active transport facilities, and developing quantitative methods for assessing road safety risk for vulnerable road users.

CRediT contribution: Data curation, Writing—review & editing.


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How to Cite

Mansell, R., Persaud, B., Milligan, C., & Pushka, A. (2024). Investigating factors that affect conflicts between bicyclists and right turning vehicles at signalized intersections. Traffic Safety Research, 6, e000040.

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