Impact of inclement weather on traffic and signal timing plan optimization of intersections in Nagaoka, Japan
CovenanteeNagakoa University of Technology
Document typeMaster thesis
Rights accessOpen Access
Adverse winter weather conditions have an impact on traffic flow and safety. Implementation of traffic management strategies to mitigate this negative effect is an area of great interest and research in transportation. Timing modification measurement is one of the most cost-effective options to improve traffic flow. However, only a few studies, all carried out in North America, have tested the effectiveness of new signal control plans in simulation or field measurements in inclement weather conditions. The purpose of the present study, carried out in the city of Nagaoka, Japan, is twofold: a) to estimate the impact of inclement weather on saturation flow rate, start-up lost time, and free-flow speed, at two signalized intersections, b) to analyze the feasibility and benefits of implementing an optimized weather responsive signal control plan to improve traffic in severe winter weather. Traffic parameters were extracted from video footage collected at two signalized intersections under inclement (January and February 2018) and normal (April 2020) weather. After appropriate data analysis and reduction, results showed an important effect of severe weather on traffic flow, resulting in an overall 24% decrease of saturation flow rate: 34% at Koshōji and 14% at Kanamecho. Effect on start-up lost time, however, was not clear. To assess the possible benefits of implementing weather-specific plans, a microscopic traffic model was developed using AIMSUM software. Model parameters were adjusted to represent current inclement weather traffic conditions, and simulate an alternative signal control plan that would improve the intersections operability under severe weather circumstances. Results from the study indicated that the implementation of a weather responsive traffic signal timing plan could benefit the overall performance of the intersections in Nagaoka.