Trajectory simulation of emergency vehicles and interactions with surrounding traffic

Abstract

Emergency services play an important role in the life of a city and are subject to constant public scrutiny. Te efcient dispatch of emergency vehicles (EMVs) requires realistic shortest-path algorithms involving the movement of EMVs within an urban network underemergencyconditions. Trip-time estimates used in shortest-path algorithms would be much more precise if it were possible to model more realistically the interactions between EMVs and surrounding trafc, as well as the reactions of other vehicles in the presence of an EMV.Terefore, EMVtrajectories shouldbestudied at themicroscopic level to accurately model the impact of EMV travel along a path shared with other vehicles. In this research, we develop three models to incorporate specifc non-EMVreactionsassociated with changing lanes, mounting the sidewalk, and approaching an intersection, plus two algorithms to actuate trafc lights at signalized intersections. Tese models and algorithms were coded in commercial microscopic trafc simulation software through the implementation of an application programming interface (API) designed to overcome the limitations of the software to realistically simulate disturbed trafc conditions and anomalous nonemergency vehicle driver behaviour observed in the presence of an EMV. Basic information about these real-world efects was gleaned from video footage recorded in Santiago, Chile, by trafc cameras, fre truck-mounted cameras, and truck-originated GPS pulses. To validate the design, a real EMVtrip captured bythe footagewas simulated bythe API.Tesimulationconsiderably reducedthe degreeoferror in delineating the path followed by the EMV compared to the default simulations generated by most commercially available software, thereby demonstrating that the API can provide highly accurate estimates of EMV trip times in an emergency context.