Add to ORKGThe object of the bachelor’s thesis was to study a code of a traffic simulator TRASI, to find causes of a malfunction in giving way at the crossing and to fix these causes. Several methods of solution were suggested and one was selected and implemented into the simulator (the priority mask system). The solution’s functionality has been tested on three simple model situations. On a crossing with a main road, on a crossing with a right road priority and on a crossing with traffic lights. The design of these situations is as well the part of the bachelor’s thesis. Then there is a brief manual for the simulator, both for users and the following programmers, in the thesis