Development Of A Freeway Incident Rating System

Abstract

A freeway incident rating system is proposed to classify incidents in terms of their disruptive potential to cause delays, fuel wastage, secondary accidents, and other adverse operational impacts. A two-dimensional rating scale is used which classifies incidents in terms of their severity and the number of agencies required to respond and clear incidents. Variables used in characterizing the severity include number of vehicles involved, number of lanes and shoulders blocked, time of incident occurrence, duration of incident until full clearance, and weather conditions at the time of the incident.

The objective behind the development of such a rating system is two-fold. First, it provides a systematic and standard way of organizing the information about the number of incidents of various severity occurring in a freeway network over a time period. This would be particularly helpful in analyzing incident data to identify temporal and spatial trends in a freeway network and to monitor and quantify the efficacy of incident prevention and response efforts. A second objective, once some experience has been gained in rating incidents, is to allow traffic management centers to rate incidents at their onsets in terms of their potential severity. Communicating those ratings using a commonly understood terminology to all responding agencies could then result in a more coordinated response to the incident, thus accelerating return to normalcy and minimizing adverse impacts such as user delays and secondary accidents.