TRA-936: MODIFYING SIGNAL CONTROL AT INTERSECTIONS UNDER ADVERSE WEATHER CONDITONS

Adverse winter weather has always been a cause of traffic congestion and road collisions. To mitigate the negative impacts of winter weather, transportation agencies are under increasing pressure to introduce weather responsive traffic management strategies such as adaptive control of signalized intersections and variable speed limits. Currently, most traffic signal control systems are designed for normal weather conditions and are therefore suboptimal in terms of efficiency and safety for controlling traffic during winter snow events due to the changing traffic patterns and driver behavior. The main objective of this research is to explore how to modify traffic signal control under adverse weather conditions. This research consists of two main components. First, we have examined the impacts of winter weather on two key traffic parameters, i.e., saturation flow rate and start-up lost time. Both parameters were measured from 16 hours of traffic video footage at one intersection. Secondly, we have investigated the potential benefits of implementing weather-specific signal control plans for isolated intersections as well as arterial corridors based on two case studies. Three traffic demand scenarios, i.e., high, medium, and low, were considered. We developed weather-specific signal plan alternatives for each scenario based on the traffic parameters measured in winter weather. Evaluation results show that implementing such signal plans is most beneficial for intersection with a medium level of traffic demand. It is also been found that the benefit of implementing weather-responsive plans was more compelling an arterial-corridor level with signal coordination than at an isolated-intersection level