Microscopic Road Safety Comparison Between Canadian and Swedish Roundabout Driver Behaviour
Author(s): Paul St-Aubin, Nicolas Saunier, Luis Miranda-Moreno, Aliaksei Laureshyn
Slidedeck Presentation:
Abstract:
'Despite similar population densities, levels of urbanization, climates, and levels of economic development, road accidents across the province of Quebec (and the rest of Canada) are twice as high as in Sweden, as measured by accident frequency and severity. Some of this disparity may be explained by differences in road geometry, but some of this disparity is hypothesized to also be attributed to latent behavioural factors present in the general population. The objective of this research is to investigate latent differences in road user behaviour that may explain differences in accident history beyond any road safety effects derived from road design and traffic composition. A number of roundabouts in Quebec and Sweden are selected on the basis of similarity in design, for cross-sectional comparison. The modern roundabout is chosen as a case study as its implementation in North America is identical to that of Europe (where the design originated), and because roundabout operation relies heavily on road user behaviour (right-of-way is performed exclusively through rules of priority). This approach to intersection control is in stark contrast with typical stop-sign and traffic light control used throughout North America.
Analysis is performed using automated computer-vision-based trajectory extraction of road users from video data, coupled with surrogate safety methods to analyse behaviour and resulting safety proactively. Surrogate safety measures of interest for this study include speed and time-to-collision, modeled using motion-pattern motion-prediction. Accident records recorded at the sample of roundabouts studied are found to be consistent with national averages of each country respectively (twice as high and severe in Quebec as in Sweden). After controlling for various geometric design features, land use, construction year, traffic exposure, and traffic patterns, an overall tendency of lower speeds and fewer serious conflicts (as measured by time-to-collision) are found at the Swedish roundabouts. Results: Accident records recorded at the sample of roundabouts studied are found to be consistent with national averages of each country respectively (twice as high and severe in Quebec as in Sweden). After controlling for various geometric design features, land use, construction year, traffic exposure, and traffic patterns, an overall tendency of lower speeds and fewer serious conflicts (as measured by time-to-collision) are found at the Swedish roundabouts. These results are found to be consistent with local and national accident records, and would suggest that some important latent regional factors possibly related to educational or enforcement factors are at play at the microscopic level. Further investigation of these regional factors is warranted. '