Vehicular Conflict Assessment on a Road with Lane Reduction Using the SSAM Methodology

In this article, an evaluation of the number of vehicular conflicts is carried out, in a section of road that is part of a traffic light intersection, with constant presence of traffic jams. In the trajectory of this section there is a reduction in lanes, variable lane widths and little uniformity, causing a bottleneck that produces different types of conflicts between vehicles. To carry out the evaluation, the VISSIM microsimulation software was used, here the real situation of the intersection is modeled and two new scenarios are proposed, in which geometric redesign proposals are made in the infrastructure of the section of road, in order to analyze variability in the number of vehicular conflicts. For the automatic counting of conflicts, the Surrogate Safety model (SSAM) is used. Vehicular conflicts are categorized according to their crossing collision angle (crossing), rear end collision angle (rear end) and lane change (lane change), and their severity levels in relation to the time before collision (TTC). The results indicate a count of 3916 conflicts in the microsimulation of the real situation. In the first proposed scenario, 2,231 conflicts were counted, which corresponds to a 43% reduction in relation to the current situation; while in the second scenario 3,835 conflicts were counted, a reduction of 2%. The TTCs ranged between 0.52 and 0.70, indicating a high risk of collision on the road.