title: Are signalized intersections with cycle tracks safer? A case-control study based on automated surrogate safety analysis using video data.
abstract: Cities in North America have been building bicycle infrastructure, in particular cycle tracks, with the intention of promoting urban cycling and improving cyclist safety. These facilities have been built and expanded but very little research has been done to investigate the safety impacts of cycle tracks, in particular at intersections, where cyclists interact with turning motor-vehicles. Some safety research has looked at injury data and most have reached the conclusion that cycle tracks have positive effects of cyclist safety. The objective of this work is to investigate the safety effects of cycle tracks at signalized intersections using a case-control study. For this purpose, a video-based method is proposed for analyzing the post-encroachment time as a surrogate measure of the severity of the interactions between cyclists and turning vehicles travelling in the same direction. Using the city of Montreal as the case study, a sample of intersections with and without cycle tracks on the right and left sides of the road were carefully selected accounting for intersection geometry and traffic volumes. More than 90h of video were collected from 23 intersections and processed to obtain cyclist and motor-vehicle trajectories and interactions. After cyclist and motor-vehicle interactions were defined, ordered logit models with random effects were developed to evaluate the safety effects of cycle tracks at intersections. Based on the extracted data from the recorded videos, it was found that intersection approaches with cycle tracks on the right are safer than intersection approaches with no cycle track. However, intersections with cycle tracks on the left compared to no cycle tracks seem to be significantly safer. Results also identify that the likelihood of a cyclist being involved in a dangerous interaction increases with increasing turning vehicle flow and decreases as the size of the cyclist group arriving at the intersection increases. The results highlight the important role of cycle tracks and the factors that increase or decrease cyclist safety. Results need however to be confirmed using longer periods of video data.
authors.affiliation: Department of Civil Engineering and Applied Mechanics, McGill University, Room 165, Macdonald Engineering Building, 817 Sherbrooke Street West, Montréal, Québec, Canada H3A 0C3. Electronic address: sohail.zangenehpour@mail.mcgill.ca.
authors.forename: Sohail
authors.initials: S
authors.lastname: Zangenehpour
authors.affiliation: Department of Civil Engineering and Applied Mechanics, McGill University, Room 165, Macdonald Engineering Building, 817 Sherbrooke Street West, Montréal, Québec, Canada H3A 0C3. Electronic address: jillian.strauss@mail.mcgill.ca.
authors.forename: Jillian
authors.initials: J
authors.lastname: Strauss
authors.affiliation: Department of Civil Engineering and Applied Mechanics, McGill University, Room 268, Macdonald Engineering Building, 817 Sherbrooke Street West, Montréal, Québec, Canada H3A 0C3. Electronic address: luis.miranda-moreno@mcgill.ca.
authors.forename: Luis F
authors.initials: LF
authors.lastname: Miranda-Moreno
authors.affiliation: Department of Civil, Geological and Mining Engineering, Polytechnique Montréal, C.P. 6079, succ. Centre-Ville, Montréal, Québec, Canada H3C 3A7. Electronic address: nicolas.saunier@polymtl.ca.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Saunier
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control*; D000328:Adult; D001642:Bicycling / Q000293:injuries*; D016022:Case-Control Studies; D004779:Environment Design; D006801:Humans; D016015:Logistic Models; D011792:Quebec; D012449:Safety; D017751:Safety Management; D014741:Video Recording
keywords: Cycle track; Cyclist safety; Random effects model; Surrogate safety measure; Video analysis