In this paper an emergency service vehicle (ESV) location problem has been considered in which it is assumed that each emergency call may require more than one ESV. In ESV location problem two factors should be known; the location of stations and the number of ESVs at each station. Hence, a nonlinear mixed integer programming model is presented in order to maximize the total response rate to the emergency calls. Moreover, a solution method based on genetic algorithm is provided and efficiency of the algorithm is evaluated with regard to the results from an exhaustive enumeration method. The model is applied to the real case study based on the data from Mashhad city to find the emergency gas stations and the required ESVs. Finally, a sensitivity analysis on the main parameter of the model is conducted and the managerial insights are reported. The results indicate that considering the fact that each call may require more than one ESV is very influential on the response rate and the assumption of each call requires just one ESV makes the results unrealistic.

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