Paul St-Aubin edited Introcution.tex  almost 10 years ago

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Roundabouts are a relatively new design for intersection traffic management in North America. With considerable promises from abroad in terms of safety, as well as capacity---roundabouts are a staple of European road design---roundabouts have only recently proliferated in parts of North America including the province of Québec. However, questions still remain regarding the feasibility of introducing the roundabout to regions were driving culture and road design philosophy differs and where drivers are not habituated to their use. This aspect of road user behaviour integration is crucial for their implementation for roundabouts manage traffic conflicts passively. In roundabouts, road user interactions and driving conflicts are handled entirely by way of driving etiquette between road users: lane merging, right-of-way, yielding behaviour, and eye contact in the case of vulnerable road users are all at play for successful passage negotiation at a roundabout. This is in contrast with typical North American intersections managed by computer-controlled traffic-light controllers (or on occasion police officers) and traffic circles of all kinds which are also signalised. And while roundabouts share much in common with 4 and 2-way stops, they are frequently used for high-capacity, even high-speed intersections where 4 and 2-way stops would normally not be justified. Resistance to adoption in some areas is still important, notably on the part of vulnerable road users such as pedestrians and cyclists \cite{Hyd_n_2000, Stone_2002, Gran__2011, Perdomo_2014} but also by some drivers too.  While a number of European studies cite reductions in accident probability and accident severity, particularly for the Netherlands , \cite{Schoon_1994},  Denmark \cite{Jensen_2013}, Sweden \cite{Bergh_1997, Hyd_n_2000}, research on roundabouts in North America is still limited, and even fewer attempts at microscopic behaviour analysis exist anywhere in the world. The latter is important because it provides insight over the inner mechanics of driving behaviour which might be key to tailoring roundabout design for regional adoption and implementation efforts. Fortunately, more systematic and data-rich analysis techniques are being made available today. This paper proposes the application of a novel, video-based, semi-automated trajectory analysis approach for large-scale microscopic behavioural analysis of 20 of 100 available roundabouts in Québec, investigating 37 different roundabout weaving zones. The objectives of this paper are to explore the impact of Québec roundabout design characteristics, their geometry and built environment on driver behaviour and safety through microscopic, video-based trajectory analysis. Driver behaviour is characterised by merging speed and time-to-collision \cite{Laureshyn_2010}, a maturing indicator of surrogate safety and behaviour analysis in the field of transportation safety. In addition, this work represents one of the largest applications of surrogate safety analysis to date.