Dynamic Shortest Path in Ambulance Routing Based on GIS
要旨Using geospatial information system (GIS) in emergency vehicles offers a valuable tool for network analysis, visualization and management. It generally offers tools to find the shortest or fastest route through a network. These capabilities of GIS for analyzing spatial networks enable it to be used as a decision support system for dispatching and routing of vehicles. The efficient management of ambulance routing to the incident sites and then to the closest hospitals is a vital aspect of the quality of health services offered to citizens. Accomplishing an effective ambulance routing minimizes its response time and thus improves the response performance. This paper describes the development of a new dynamic routing system that offers a solution to the problem of ambulance routing. In urban areas response time of emergency vehicles is influenced by traffic congestion. Dynamic vehicle routing considers the changes of traffic congestion in computing the shortest path. The proposed system is based on integration of GIS and real-time traffic conditions. In this system historical traffic data has been used to determine an initial ambulance path using Dijkstra algorithm. Then the real- time traffic data related to traffic congestion is applied to update the emergency route. A dynamic shortest path is used for emergency vehicle routing. Results of this study illustrate that dynamic routing of emergency vehicles is much more efficient than the static solution. This efficiency is highlighted when unforeseen traffic congestion due to an incident is accounted for. The major contribution of the paper is the way an integrated dynamic ambulance routing system has been developed which has improved emergency response time by about 20%.