Development of Safety-Based Level-of-Service Parameters for Two-Way Stop-Controlled Intersections

Abstract

Current methods for evaluating level of service at two-way stop-controlled intersections do not account for safety considerations. One of the most important factors influencing intersection safety is the availability of adequate sight distance. However, current recommended intersection sight distance criteria do not explicitly consider variability in traffic composition, vehicle characteristics, pavement conditions, or driver characteristics such as perception-reaction time and minimum gap acceptance. Research was therefore undertaken to develop and validate a method where the safety of a two-way stop-controlled intersection could be estimated based on parameters such as intersection geometry, traffic volume, pavement condition, traffic composition, and available sight distances. Simulation modeling was used to estimate the frequency of potential conflicts or collisions resulting from sight distance restrictions. The potential severity of the collisions was modeled using kinetic energy principles. A method for incorporating the results into a level-of-service evaluation framework was then developed.