Locating Emergency Response Facilities in the Metrorail System: A Decision Support Tool

Large public transportation systems, like that of the Washington Metropolitan Area Transit Authority (WMATA), must appropriately locate response personnel to respond quickly to emergencies throughout the Metrorail system. This is particularly challenging in sprawling and congested metropolitan areas like Washington, DC. The aim of this project is to support the WMATA Office of Emergency Preparedness (OEP) in determining appropriate geographic locations for response personnel with reduced response times to all areas of the Metrorail system. To that end, we developed a simulation model that evaluates response times to emergencies at WMATA Metrorail stations. The model relies on historical data of WMATA emergency incidents to generate probability distributions of incidents, and queries Google Maps application programming interface (API) using Python to provide responder travel times that account for the traffic at that time of day. The user inputs the proposed responder locations (one or several bases) and the tool outputs the response times to a set of emergencies. Resulting response times are then analyzed, visualized, and compared across scenarios, using response time distributions and geographic heat maps, to show response times for the system overall as well as specific stations or geographic areas. In collaboration with the WMATA OEP, we evaluate several scenarios involving moving their current OEP base to a more central location and/or allocating response personnel to different geographic areas. Based on these results, we recommend better locations for WMATA response personnel, which could improve response times by up to 27 minutes or 67% throughout the Metrorail system. While these results are specific to WMATA, the tool could be easily adapted to other public transit systems to support decisions on the location of emergency response personnel.