Public transportation is perceived as being attractive to the passengers, when it's fast, punctual, and vehicles move in optimal way across the transportation network area. Time based analysis performed in different cities proved that waiting for the right traffic signal takes more than 30% of the whole journey time. Traffic light priority for trams and buses significantly improves their movement and punctuality.

Presented system helps vehicles to drive through an intersection where traffic is controlled by light signals. Vehicular unit sends a series of messages to traffic light controller with information about its route and vehicle status. Priorities assigned on different cross-roads make it possible to shorten the total ride time, what leads to lower company's outlay and increased passengers satisfaction.

Information from the vehicle is sent twice or thrice when it moves past defined control points. Controller's logic circuit analyses received information from every vehicle that occur near the crossing, and modifies light sequence by advancing or retarding their time on desired movement direction. After the vehicle leaves the junction, the vehicular unit sends information to the controller one more time.

Traffic light priority system in cooperation with SNRP has many advantages:

• The same vehicular unit that is primarily used for voice communication with surveillance headquarter is used for traffic signal priorities.
• SNRP helps to localize the signal transmission spot precisely - vehicles receive green light exactely when they need one.
• It is possible to give priority to specific vehicles only (e.g. only to delayed ones), what makes deviations from the schedule equal to all the trams.
• Priority signals are sent automatically, without any participation from the driver.