Evaluating Freeway Service Patrols in Low-Traffic Areas Using Discrete-Event Simulation

Abstract

Freeway service patrol (FSP) is a low-cost but effective method to identify and clear incidents quickly on freeways, and it has been widely implemented in United States. Most of the related literature focuses on evaluating the reduction of travel delay and secondary collision because of a quicker incident clearance. Although such measures are major concerns in urban areas, they may be of less concern in low-traffic areas. A major function of FSP in low-traffic areas is to assist stalled vehicles, protect stranded drivers, and provide free road assistance services, but its major benefit is to bring direct savings to stranded drivers. This paper presents a new benchmark to evaluate the benefit-cost ratio of FSP in low-traffic areas based on a customized event-driven simulation model. The event-driven simulation model is better than the analytical models and microscopic simulation in this context in that it can accommodate more details than an analytical model while achieve a faster simulating speed than microscopic simulations when the road network is large and the simulation period is long. Lastly, the Safety Assistance for Freeway Emergencies (SAFE) Patrol in Kentucky is evaluated by using the method in this paper to evaluate and estimate the benefit-cost ratios of SAFE Patrol under different scenarios.