Vehicular Conflict Assessment on a Road with Lane Reduction Using the SSAM Methodology (#499)

Authors

Del Valle, Marco

La Rosa, Xiomara

Silvera, Manuel

Campos, Fernando

Silvera, Manuel

Palacios-Alonso, Daniel

Abstract

In this study, an evaluation of vehicular conflicts in a road segment that forms part of a signalized intersection, which is characterized by persistent traffic congestion, is performed. This road segment is plagued by a reduction in lanes, variable lane widths, and a lack of uniformity, leading to the formation of a bottleneck that triggers a whole branch of conflicts between vehicles. In order to carry out the assessment, VISSIM, a microsimulation software, was utilized. This software was used to model the real-life situation at the intersection, and two new scenarios were devised. These new scenarios involved proposals for the geometric redesign of the road segment infrastructure, with the aim of analyzing the variability in the number of vehicular conflicts. For automatic conflict counting, the Substitute Safety Assessment Model (SSAM) was employed. Vehicular conflicts were classified according to their collision angle at crossing (crossing), collision angle at rear end (rear end), and lane change (Lane Change), as well as their severity levels in relation to time to collision (TTC). The results reveal a count of 3916 conflicts in the microsimulation of the real-life situation. The first proposed scenario resulted in a count of 2231 conflicts, a reduction of 43% compared to the current situation, while the second scenario resulted in a count of 3835 conflicts, a reduction of 2%. The average values of the TTC oscillated between 0.52 and 0.70 seconds, which indicates a high risk of collision on the road.