The Integration of Conflict Probability and Severity for the Safety Assessment of Intersections

The use of traffic crash data-based methodologies for safety evaluation is inadequate due to the shortcomings such as unavailability and low quality of historical crash data. Other than crash data-based analysis, the use of empirical vehicle maneuvers and/or the development of micro-simulation models in conjunction with surrogate safety measures has been shown to potentially complement traditional safety analysis. However, several previous works found that existing surrogate measures for intersection safety assessment, such as post-encroachment time, time to collision and speed, fail to simultaneously represent conflict probability and severity. Thus, this study proposes a measurement of the crash hazard that considers crash occurrence probability as well as expected severity. By utilizing the change in the total kinetic energy before and after the collision, angle of collision and PET, the proposed conflict index is derived and its implications are discussed. Several video-recorded si