The chronological sequence of events performed by the major components (police, mechanical,and communication service) of an emergency service system in responding to freeway incidents has been represented in a simulation model so that the performance of the system can be analysed systematically. Thirty selected candidate systems, based on possible combinations of major detection and service subsystems,were simulated on the San Francisco-Oakland Bay Bridge by using a set of historical incident data. The performance of alternative systems was evaluated separately by a cost-effectiveness analysis and a total system cost procedure. The cost measure was expressed in dollars.the merit of various effectiveness measures was discussed,and their correlations were shown. The total delay to all motorists affected by the incident was selected as the representative effectiveness measure for the evaluation. Total system costs for different values of time ranging from $0/hour to $5/hour were presented. At a value of time of $3/hour, both analyses resulted in the same best 5 systems in the same order.the most promising system of the 30 systems tested was the one with call-box units spaced at quarter of a mile intervals, 2 stationary police units, and 3 stationary mechanical service units. The model has the potential to be extended to include other system components, such as medical service, and can be applied to different locations. (A)
Abstract