Difference between reported crash me and speed disturbances in urban signalized intersecons: a case study in Fortaleza, Brazil

Abstract

The advent of new technologies for monitoring and controlling traffic allows the development of more robust road safety studies, based on the collec%on of disaggregated traffic data at intervals of 1 to 15 minutes or even in real %me. However, in order to relate the crashes to their precursor condi%ons, applying this type of data requires a be8er knowledge on the accuracy of crash reported %mes. This work aims to present an analysis between the reported %mes of crashes and disturbances in the traffic flow condi %ons in urban signalized intersec%ons in Fortaleza, Brazil. Vehicle flow disturbances were detected from speed oscilla%ons by using an algorithm based on comparing speeds between “typical” and “crash” condi%ons and by valida%ng the detec%ons with visual analysis. The results of inves%ga%ng 291 crashes showed an average difference of 20 minutes (sd = 23 min) between the reported %me of crash and the occurrence of the speed disturbance. This is an indica%on that, while developing road safety disaggregated analyses, one should examine the database accuracy regarding the crash reported %me.