Investigating Factors that Influence the Location and Time Intervals between Primary Incidents and Secondary Crashes

Abstract

Mitigating secondary crashes is one of the priorities in traffic incident management, but limited information on these incidents can hinder the selection of appropriate mitigation efforts. This study aimed to investigate the factors that influence spatiotemporal gaps (i.e., distance and time) between primary incidents and secondary crashes. The analysis was based on data collected from 261,153 incidents from 2017 to 2019 on the entire length of Route I-95 in Florida. The study used HERE speed data to identify secondary crashes. It identified 3,906 crashes that were secondary to 3,547 primary incidents, accounting for 1.5% of the total incidents analyzed. The average distance and time gaps between primary incidents and secondary crashes were found to be 1.6 km (1.0 mi) and 43.2 min, respectively. The analysis revealed that 46.5% of secondary crashes occurred within 45 min and 1.6 km (1.0 mi) upstream of primary incidents. The study used hazard-based models to investigate the factors that influence spatiotemporal gaps. The models revealed that peak hours, left or right shoulder closure, and higher traffic volume significantly increased the distance gap. Conversely, partial or full lane closure and the number of lanes significantly decreased the distance gap. Incident type, left or right shoulder closure, and traffic volume significantly increased the time gap, whereas morning peak hours, four-lane roadways, and vehicle speed significantly decreased the time gap. Overall, knowing the factors influencing the distance and time gaps can help incident managers and responders make better-informed decisions, take more effective actions, and manage incidents more efficiently.