EMVLight: A multi-agent reinforcement learning framework for an emergency vehicle decentralized routing and traffic signal control system

Every Second Counts: A Comprehensive Review of Route Optimization and Priority Control for Urban Emergency Vehicles

“…EMV-DRO has shown significant advancements over EMV-SRO, even when not combined with EMV-TPC strategies at intersections and on road links [68]. Further, considering the differences regarding driving policies between various EMVs and SVs, researchers began to focus on EMV-ROAS algorithms to reduce EMV response times by combining EMV-SRO/DRO with additional support from traffic departments, including EMV-TPC at intersections [68,69], lane reservation on road links [70,71], and emergency broadcast [72] to minimize EMV response times. Gedawy [68] combined a dynamic route planning algorithm based on the D* Lite informed search algorithm with signal priority control to reduce the travel times of EMVs further.…”

“…This framework was designed to reduce the travel times of EMVs. Su et al [71] proposed a decentralized Reinforcement Learning (RL) framework called EMVLight, which combined dynamic EMV routing and traffic signal priority control to minimize the travel times for both EMVs and SVs. Dutta et al [73] introduced a strategy that integrated vehicle rerouting and traffic signal optimiza-tion at intersections, modeling the urban dynamic traffic environment with priority vehicle passage requirements as a bilevel optimization problem.…”

“…In Stage 2, EMVPS commonly employ light/infrared-based [80], sound-based [81], fixed sensors-based [82], radio-based [76,83], GPS-based [84,85], and VANET-based [71,86] solutions to detect the EMV-TPC demand within the control area, as shown in Fig- ure 5. Upon detection of the entry of an EMV or receiving a request from an EMV, the traffic signal controller (TSC) can be quickly activated to remain or turn green upon confirmation of the request.…”

“…Consequently, network-based optimization methods have been proposed that focus more on coordinating multiple intersections at the network scale to additionally mitigate the adverse effects on the road network resulting from prioritizing EMVs [71,79,86,91]. Petrică et al [91] proposed a traffic light priority control system for EMVs and public transportation that reduced average emergency response times and optimized traffic flow at intersections.…”

“…This method was tested within a traffic road network simulated by the SUMO software. Su et al [71] introduced a decentralized RL framework designed for the dual purpose of dynamically routing EMV and controlling traffic signal priorities. The methodology allowed EMVLight to master cooperative traffic signal phasing strategies at the network level, which not only cut down on the travel times of EMVs but also shortened the travel times of SVs.…”