The city of Zagreb is confronted with a long – lasting increasein motorization rate. City streets are saturated with private cars, therefore in peak hours most of the city road network is congested. Network congestion leads to time and financial losses, and with this state emission of air pollutants and noise reach their peak levels. Modal split change in favour of public transport and sustainable transport variations is a key measure to reduce negative effects on the environment. Low operating speed of light rail subsystem in the City of Zagreb presents a problem which is making that transport mode less attractive. By implementing adaptive traffic control systems it is possible to reduce congestion and give priority to public transport vehicles. Tram subsystem is the dominant mode in the City of Zagreb and therefore giving priority on signalized intersections to trams would increase operating speed of tram subsystem. The implementation of adaptive traffic control can reduce time travel, and increase level of service.