Simulation of a Computer Aided Routing System (CARS)

CARS is s system designed to provide a taxi-like service at a mass transit-like cost. It allows potential passengers to request service from their via telephone, with calls being processed by a central computer facility. The computer periodically executes a routing algorithm which assigns vehicles to passengers and communicates this routing information to the vehicles. The system is 'real time' in that it will pick up a passenger and shortly after a request will deliver him to his destination within a guaranteed time (with a minimum number of deviations for collecting and delivering other passengers). The key to CARS is the routing algorithm. Since labor and vehicular costs are a major portion of the total system cost, an algorithm is required which can provide an effective dynamic service with a minimum number of vehicles. A variety of such algorithms have been proposed, but these algorithms can not be evaluated in an analytic fashion. Hence, a comprehensive simulation model has been developed to test and compare these routing algorithms. The model facilitates the investigation of relationships between such parameters as number of vehicles and quality of service. This paper describes the methodology of the simulation model and the economic gains (in terms of the need for fewer vehicles) realized through its use. The use of an ARDS storage tube display to produce graphical output from the model is also discussed.