A case study to identify secondary crashes on Interstate Highways in Florida by using Geographic Information Systems (GIS)

With the rapid development of the traffic infrastructure, the cost of the traffic congestion keeps increasing, reaching $124 billion in 2013. The previous study indicates that traffic incidents led to more than 25% of the traffic congestion, and the risk of secondary crash occurrence with the primary incidents is six times higher than that in the normal traffic condition. As identifying secondary crashes used to be very labor-intensive and time-consuming, this study aims to find a more efficient method for the secondary crash identification. Currently, using Arc GIS is of great interest in traffic safety analysis. ArcGIS is a widely applicable software package that allows the users to analyze data by collecting, storing, controlling and geographically displaying it. This study used Arc GIS as the main tool to link the primary incidents and the secondary crashes within certain determined spatial-temporal criteria and propose two filters to reduce the crashes that fail to meet the secondary crash assumption. The two filters selected the crashes that occurred in the same direction and downstream of the primary incidents.