<p>Ambulance routing optimization has been in the spotlight in recent years. Researchers have tried to modify traditional vehicle routing problems to model and examine real-world logistics and transportation-related problems. In the healthcare sector, being able to choose an Emergency Medical Service (EMS) to handle a call and to decide which segments emergency should respond to at the scene and when there is a need for transport action are crucial to decreasing response times and increasing the efficiency of an EMS. In this study, a new ambulance routing and emergency medical service (EMS) selection optimization model is presented. In the model, a customized Service Availability" is proposed to be included in the routing. OpenStreetMap for Pathfinding was adopted for the experiment of the EMS routing and dispatching decisions model of some case studies. The main criteria of the studies are “Start Node”,”Random Accident Node”, “Node Paths”, “Distance (KM)”, and “Selected EMC”. The experiments result shows that the “Service Availability” distribution of critical resources like specialists, and critical care units across EMS centers are selected across the EMS center labeled “115,881: and has a balanced availability of all other services, making it a strong candidate for the route selection. This solution significantly is a better solution than the constraint shortest path method in terms of response time only.</p>