AbstractsEngineering

Cycling as a mode of travel is becoming more popular especially in urban areas like Montreal, Canada. With this reality come serious concerns for cyclist safety and health. These concerns have initiated the need to study the determinants of cyclist injury risk as well as cyclist exposure to traffic-related air pollution. These two issues are particularly important at intersections where cyclists are exposed to high vehicular traffic and as a result are exposed to the risk of collisions and air pollution. With the goal of improving road safety and reducing cyclist exposure to air pollution, this report seeks to meet the following objectives, to: i) investigate the impact of motor-vehicle traffic, geometric design and built environment factors on cyclist injury occurrence and bicycle activity at signalized intersections in Montreal and ii) study the association between bicycle activity (volume) and traffic-related air pollution concentrations. As an application environment, this research makes use of a large sample of signalized intersections on the island of Montreal. In this work, cyclist injury risk was examined looking not only at aggregate cyclist and motor-vehicle flows passing through intersections but also at disaggregate traffic movements and potential conflicts. It was found that a 10% increase in bicycle flow is associated with a 5.3% increase in the frequency of cyclist injuries whereas a 10% increase in motor-vehicle flow would result in a 3.2% increase in cyclist injury occurrence. When disaggregating motor-vehicle flows into its constituent movements it becomes apparent that right turn movements have the greatest effect on injury occurrence. The conflict measure again confirms this result. Regarding the geometric design and built environment factor analysis, the presence of an arterial and bus stops were found to increase cyclist injury occurrence whereas protected left turn signals, pedestrian signals with countdown and there being three approaches instead of four were found to have the opposite effect on cyclist injury risk. From a health perspective, applying the nitrogen dioxide (NO2) land use regression model for Montreal, has revealed some interesting results. It was found that NO2 levels are highest in the central neighbourhoods of the island of Montreal which is also where cyclist flows are the greatest. The central neighbourhoods are also where Montreal's bicycle network is most dense and most frequented. Also, the corridor analysis revealed that corridors with a bicycle facility have more than twice as many cyclists as those without any facility but they also have, on average, higher air pollution levels. To investigate the indirect impact of built environment and bicycle infrastructure on the two variables of interest (cyclist injury risk and air pollution exposure at intersections), the determinants of bicycle activity were investigated. For this purpose, a bicycle activity modeling framework was developed to measure the impact of built environment, road and transit network attributes and…