An Emergency Vehicle Routing Model in Small and Medium Transportation Networks

These days, emergency request responding in a short time is a highly challenging issue. The main goal of current research is modeling an optimization problem for emergency vehicle routing on small and medium-sized networks and solving the problem by a novice algorithm. The suggested algorithm inputs are the network, location and number of requests, vehicles, and hospitals. The objective is to minimize total travel time of vehicles plus the time that the last request is responded completely. The algorithm output is the vehicle and hospital assignment to each request and requests' responding order on the network. After developing the mathematical model of the problem, 138 random samples are produced on a network with 7 nodes and 16 links. The number of feasible answers, which is depended on the number of requests, vehicles, and hospitals, is tried to be reduced by assuming a fixed order for responding the requests. Hence, 3 different scenarios of request order are examined and it is found out that arranging the requests based on distance from the nearest vehicle results in better answers (lower total travel times). An innovative algorithm is presented for solving the problem which reduces the solving time to 5 seconds; while finding the precise answer needs time up to 810 seconds. The results show that the difference between more than 80 percent of answers found with the suggested algorithm and the precise answer is lower than 10 percent and this difference is less than 30 percent in more than 94 percent of the answers.