Simulation of Preemptive Traffic Light Control for Emergency Vehicles

Zbog sve veće prometne potražnje i razvoja društva, u urbanim sredinama broj vozila sve više raste, ali se prometna infrastruktura ne mijenja značajno. Utjecajem urbane okoline i ograničenja, često više nije moguće širiti prometnu infrastrukturu. Zbog takvih uvjeta dolazi do sve više prometnih zagušenja i nesreća. Budući da se infrastruktura fizički više ne može širiti, jedino preostaje učiniti ju pametnijom, odnosno nadograditi ju rješenjima koje nam donose Inteligentno Transportni Sustavi (ITS). Implementacija rješenja iz područja ITS-a za upravljanje semaforiziranim raskrižjem u urbanim sredinama korisnicima pruža osim rasterećenja prometa i informiranja putnika, dodatne mogućnosti poput dodjele prioriteta vozilima žurnih službi. U ovom radu je predložen i implementiran algoritam dodjele prioriteta zasnovan na praćenju položaja vozila i mjerenju duljine reda čekanja na raskrižju. Algoritam korištenjem procjene vremena dolaska žurnog vozila čisti raskrižje od vozila te osigurava bezuvjetni prioritet prolaska žurne službe kroz raskrižje. Nakon prolaska žurne službe kroz raskrižje, predložen je i implementiran algoritam za povratak oduzetog vremena kako bi se smanjio negativan utjecaj na prometnu mrežu zbog dodjele prioriteta vozilu žurne službe. Navedeni algoritmi su implementirani u programskom paketu MATLAB povezan COM sučeljem s mikroskopskim simulatorom PTV VISSIM radi njihove simulacijske provjere.Due to increasing traffic demand and the development of society, the number of vehicles in urban areas is growing, but transport infrastructure does not change significantly. By the influence of the urban environment and constraints, it is often not possible to expand the transport infrastructure. Due to such conditions, there are increasing traffic congestion and accidents. As the physical infrastructure cannot longer expand, the only thing left is to make it smarter and upgrade it with solutions that are brought by Intelligent Transport Systems (ITS). Implementation of services from the ITS area for traffic light control in urban environments not only provides users with the added convenience of delivering better traffic demand and information to passengers yet provides priority assignment to emergency services vehicles also. In this thesis, an algorithm for preemptive traffic control has been proposed and implemented based on vehicle position tracking and metering at the intersection. The algorithm uses the estimated arrival time of the emergency vehicle to clear the intersection from vehicles and ensures absolute passing priority through the intersection for the emergency service vehicle. After emergency vehicle passes through the intersection, an algorithm for returning withdrawn time has been proposed and implemented to reduce the negative impact on the traffic network by prioritizing the emergency service vehicle. Mentioned algorithms have been implemented in MATLAB that is linked using the COM interface with the microscopic simulator PTV VISSIM for their simulation testing