Évolution du nombre de piétons et d’occupants de véhicules blessés aux intersections à la suite de l’implantation de mesures d’apaisement de la circulation à Montréal
Background: For the past few years, the implantation of traffic calming measures has gained in "popularity" in Montreal; however, no study has been conducted to assess the impact of these measures on the variation in the number of road injuries in Montreal. Objective: Determine the relation between the implantation of traffic calming (curb extensions and speed bumps), and the annual variation in the number of pedestrians and vehicle occupants injured at the intersections of four boroughs of the City of Montreal between 2000 and 2014. Methods: Study design is longitudinal, before-after type with a control group. The data pertaining to the traffic calming measures were collected from professionals from the four boroughs and their actual implantation was checked using Google Street View – Time Machine. Other intersections characteristics include the estimated volumes of vehicles and pedestrians (Origin-Destination survey, 2008), the presence of major roads (metropolitan arterial roads network) and the number of roads stemming from the intersection (Open Street Map road network). The numbers of people injured at the intersections were collected from accident police reports (SAAQ). Multilevel regression analyses (Poisson), over two levels, were conducted to explain the yearly variation in the number of injured pedestrians and vehicle occupants at intersections. The analyses include the intersections specifications (A and B models) as well as the annual evolution of the number of injured people (B models). Results: Between 2004 and 2014, at least 15.0% of the intersections of the whole four districts benefited from a calming measure, mainly from 2011 and after. Taking into account the other intersections characteristics, curb extensions are associated with a 23% decrease in the number of injured pedestrians [IRR= 0,766; 95% IC= 0,633-0,928] and a 54% decrease in the number of injured vehicle occupants [IRR= 0,456; 95% IC= 0,392-0,530]. The presence of speed bumps on an adjacent road section is associated with a 54% decrease in the number of injured vehicle occupants at the intersection [IRR= 0,461; 95% IC= 0,380-0,560]. Considering also the temporal decrease in the number of injured people (B models), curb extensions [IRR= 0,696; 95% IC= 0,598-0,811] and speed bumps [IRR= 0,713; 95% IC= 0,587-0,867] are significantly associated with a decrease in the number of injured vehicle occupants. Conclusion: The strengths of the study reside in the disaggregated analysis conducted at the intersections, and in taking into account the temporal trend. The results are consistent with those reported in the literature on the preventive impacts of traffic calming measures. Moreover, our study helps improve our current knowledge in assessing the impact of two specific measures (curb extensions and speed bumps) on the number of pedestrians and vehicle occupants injured at intersections.
Traffic calming measures Built environment Curb extension Speed bump Temporal trend Google Street View Public health