ANALYTICAL FRAMEWORK FOR MINIMIZING FREEWAY-INCIDENT RESPONSE-TIME

Freeway-incident-management (FIM) programs are receiving growing attention, since they have the potential of generating substantial savings for highway users. The goal of any incident-management program is the minimization of incident delay through the rapid restoration of the freeway capacity. The most important aspect of freeway-incident management is the servicing and the removal of the incidents. Currently a number of FIM programs use a fleet of trucks for the quick restoration of freeway capacity. Although the deployment of these traffic-flow restoration units (TFRUs) is an important component of freeway-management operations, the literature lacks analytical models that can be used to rationalize the deployment of the TFRUs. The present paper proposes an integrated methodological framework for the minimization of freeway-incident delays through the optimum deployment of TFRUs. The proposed model consists of three basic modules. The first module determines the number of required TFRUs and their service territories. The second module simulates the generation of freeway incidents and the traffic-flow restoration operations to estimate the total incident clearance time for each incident. Finally, the third module estimates the freeway-incident delay based on the total incident clearance time and the geometric and traffic characteristics of the freeway under study. The proposed model can be used to determine the number of TFRUs, and their dispatch policy, to achieve a threshold value of freeway-incident delay.