In the road safety statistics we can find a big group of accidents that happened because the driver didn´t pay attention to driving. The car manufacturers are developing many new electronic assistance systems and their task is also to support driver´s attention. One of these systems is the system for keeping the traffic lane. It has to keep a car in the lane, while watching the marking on the road, when driver doesn´t enough pay attention to driving. This work wants to evaluate this system and its benefit for traffic safety. This will be made through real traffic accidents research. The target is to say, if widening of the system in new cars would reduce the number of traffic accidents or their consequences.