Traffic lights are the lights for controlling the flow of traffic which installed at crossroads. Traffic lights have an important role in regulating traffic especially crossroads. One way to overcome the traffic problem is to build a system of traffic optimization where each point of the intersection phase at the road signals automatically. This system implements fuzzy mamdani logic method with MOM (Mean of Maximum) defuzzification for this method is very simple, easy to understand and objective. The traffic optimization system can generate the maximum green light seconds at each intersection according to the officer's input. The input required by the system is the length of the set queue, the width of the regulated path, the length of the queue on the next path, and the width of the path on the regulated path. The output of this system is proven to help optimize the number of green light seconds according to crossroads conditions.