Empirical Method for Estimating Traffic Incident Recovery Time

Abstract

Incident duration and traffic recovery time are the two critical periods for any incident management process. Because incident durations are available in postevaluation analyses, the reliability of estimating incident-induced delay depends significantly on the accuracy of recovery time estimation. The dynamics of the traffic system under the combined impact of recurrent and nonrecurrent congestions are complex and thus make it difficult to quantify the incident impact from recurrent congestion. This paper extends the difference-in-travel-time method to estimate traffic recovery time by using both incident and travel time data. The proposed method uses percentile statistics to establish the background conditions that represent travelers' anticipation under incident-free conditions and then employs the concept of the difference in the travel time and the information from the incident database to estimate traffic recovery time. The variability of estimates of traffic recovery time was also obtained by using the proposed method. The case study conducted by using the proposed method revealed that the method is fairly straightforward and robust in that the “ground truth” representation of incident impacts can be captured without any model assumptions and calibrations. In addition, the method can be used to support the calculation of various measures to monitor the performance of freeway and incident management programs.