Reducing steering wheel stiffness is beneficial in supporting evasive maneuvers

Most collision avoidance systems for highway scenarios are shifting the role of the driver from manual execution to a supervisory position. In the interface design of the proposed collision avoidance system proposed in this article, the human-machine issues complicating task automation were avoided by adopting a human-centered approach. In this paper a method to preserve driver's choice and maneuver initiation through the use of a temporarily unstable steering wheel is presented. In the particular driving condition investigated in a fixed base driving simulator, the driver has to avoid an obstacle following one of two equally safe escape paths (left or right evasive maneuver). The collision avoidance system aims at supporting both available solutions by means of a haptic steering wheel interface. Two feedback modalities are used, namely torque feedback and stiffness feedback. The results of the experiment show that the haptic interface effectively reduced the number of crashes, decreased response time with at least 100 ms while reducing the control effort and activity in the most critical situations.