Abstract: To survive, industry must continue to change technology and diversify human-man machine designs to meet the ever changing needs and requirements of the modern market in terms of performance, reliability, safety and contort. As far as the human operator is concerned with this technological evolutions, he is asked to perform more or less a similar task but with a modified HM interface. Like driving a new car, the driving task remains the same but with different tools of communication with the machine and new aiding systems introduced by the new HM interface. These changes on the interface may affect the operator mental representation and may cause operating errors and accidents. Generally, it is very difficult to assess simply by common sense the impact of changes of interface on human performance of complex systems especially in critical or in emergency situations. This study presents an approach to assess the impact of a Driving Aiding System (DAS) on the performance of human driver and safety. The system DAS is a type of lane keeping which acts by firstly alerting the driver by vibrations on the steering wheel when the trajectory of the vehicle approaches the white lines and secondly, by generating a torque on the steering wheel in a way that keep the position of the vehicle between the while lines. The research is sponsored by PROMOTEUS to develop aiding systems to improve road transport safety.