Simulation-based Evaluation of Using Variable Speed Limit in Traffic Incidents

Abstract

Abstract Variable Speed Limit (VSL) systems are used to improve the traffic conditions on road by adjusting the speed limits according to current traffic situations. The variable speed limit system usually comprises of stationary detectors to estimate the traffic condition and dynamic variable message signs at predefined locations for the application of new speed limits. In connected environment, the system can recognize bottlenecks due to the incident and, further, it is possible to use direct control of the connected vehicles to adjust vehicle speeds towards the new traffic situation. In this study, we propose a variable speed limit framework based on connected vehicles environment to improve the management of non-recurrent congestion. The proposed framework is evaluated in terms of traffic efficiency, safety, and environmental impact using microscopic traffic simulation. Furthermore, economic evaluation of these strategies is performed to determine the financial feasibility of their implementation. The results indicate that the VSL system manage to improve traffic efficiency, safety and environmental impact during the incidents. However, it is found that the results depend on incident location and incident severity (number of lanes blocked, and the incident duration).