Control Strategy of Signal Transition after Emergency Vehicle Signal Preemption

Abstract

Emergency vehicle (EV) plays an important role in evacuations or rescues when emergencies occur. To insure that an EV can transfer people in danger to emergency shelters or medical assistance organizations as soon as possible, EV signal preemption (EVSP) strategy is usually adopted. After EV has passed through the intersection, traffic signal has to transfer back to normal signal timing scheme. This paper focuses on the control strategy of EV signal transitioning from EVSP back to normal operation. Considering both efficiency and fairness, the maximum vehicles passing through in per unit time during the transition period and the minimum difference between the maximum and the minimum queue length after transition are selected as objectives, and a multi-objective optimization model is presented. A nondominated sorting genetic algorithm II (NSGA-II) is designed to solve the optimization model and unique encoding and decoding methods are presented. The established model and designed algorithm are verified and the control effect is analyzed. Simulation results indicate that by adopting the control strategy obtained by the presented model, the number of vehicles passing through in per unit time during the transition period is increased and the difference of vehicle length in different directions is reduced significantly, from which we can conclude that the control method proposed in this paper has good performance.

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

“…Therefore, some researchers focused on path-based optimization, which provides route guidance and a "green wave" (i.e., signal coordination of neighboring intersections) along the rescue route [1,80,88]. Kang et al (2014) [89] proposed an EV signal coordination (EVSC) approach that provided a "green wave" for EVs.…”

“…This process may range from zero to five cycles, depending on the transition algorithm and cycle length [92]. However, limited studies proposed the transition methods after EMV-TPC operations [88,93], including the smooth transition algorithm [92], optimal control algorithm [78], MOO [88], and linear programming [79]. These algorithms aimed to minimize or maximize one or more of the optimization objectives, including minimizing transition time [79,92], minimizing queue length [78], and maximizing SVs passing in per unit time during Stage 4 [88].…”

“…However, limited studies proposed the transition methods after EMV-TPC operations [88,93], including the smooth transition algorithm [92], optimal control algorithm [78], MOO [88], and linear programming [79]. These algorithms aimed to minimize or maximize one or more of the optimization objectives, including minimizing transition time [79,92], minimizing queue length [78], and maximizing SVs passing in per unit time during Stage 4 [88]. In summary, diverse transition algorithms exhibit varied performances for intersections after the passage of EMVs.…”

Advanced Transition Preemption Strategy for Signalized Intersections near Highway-Rail Grade Crossings with Dual Tracks

“…ey developed a two-phase algorithm consisting of a relaxation method and a stepwise search strategy to solve the optimal control model. Mu et al conducted several studies of emergency vehicle preemption strategies while considering route-based applications, timed colored Petri Nets, and a nondominated sorting genetic algorithm II [23][24][25].…”

Signal Timing Optimization Model for Intersections in Traffic Incidents

“…A two-phase algorithm is developed to solve the optimal control model, which consists of a relaxation method and a stepwise search strategy [14][15][16]. An emergency vehicle signal coordination (EVSC) approach is proposed, which can provide "green wave" for EVs in signal coordination setting [17][18][19]. e timed Petri nets (TPNs) is employed by Huang et al to model preemption of emergency vehicle systems for the first time.…”