Variable speed control systems have been implemented in a number of jurisdictions throughout the world. Many of these systems have been deployed to address specific safety issues. A smaller number of systems have been deployed as a more general traffic management tool and even for these systems, there is currently limited documentation describing the quantitative safety and operational impacts. Furthermore, the impacts that are reported are primarily from systems in Europe, and may not be directly transferable to North America. This paper describes a methodology developed to evaluate the safety impacts of variable speed control systems and presents the results obtained using this methodology to evaluate a candidate variable speed control system for an urban freeway in Toronto, Canada. The keys findings from the study show that the candidate variable speed control has the potential to provide relatively large safety benefits. The study also found, however, that the safety impacts vary depending on traffic conditions; the variable speed control system logic, and the parameters within the system algorithms. Furthermore, the results are based on several important assumptions about drivers' reaction to variable speed limits. For the covering abstract of this conference see ITRD number E216511.
Samenvatting