Weather-Based Safety Analysis for the Effectiveness of Rural VSL Corridors

摘要

The purpose of this research was to develop a weather-based safety analysis for determining theeffectiveness of the Variable Speed Limit (VSL) system. The VSL system provides variable,regulatory speed limits to drivers based on real-time traffic, weather, and roadway conditions.Crashes for the winter season (October 15 to April 15) from 2007 to 2012 on four VSL corridorsalong Interstate-80 in the state of Wyoming were analyzed. For establishing the SafetyPerformance Functions (SPF), a Negative Binomial (NB) modeling technique was found to bethe preferred regression modeling technique to model the frequency of crash occurrence andexplanatory variables related to weather and the use of the VSL system. Use of weathervariables normalized the winter seasons before and after the VSL systems were implemented.The results from the analysis showed a significant reduction in winter crashes due to the use ofthe VSL systems.