In-field evaluation of the effects of Continuous Driver Support on driver behaviour.

User-related effects of a Driver Assistance System for Continuous Support on driver behaviour, were evaluated in a field test carried out in 2013. Twenty four drivers took part in test drives with a within-subject design along a 53 km test route containing motorway and rural-road sections. Driving data was logged and the test drivers were observed by means of an in-car observation method (Wiener Fahrprobe), i.e., by two observers in the car along with the driver. Questionnaires were used to assess the drivers’ comprehension of and experiences with the system, experienced usefulness of and satisfaction with the system, as well as willingness to have and pay for the system. The results showed that there was no difference in general speed behaviour while driving with the system compared to driving without. The Curve Speed Warnings gave the expected effect. There were less dangerous lane changes with the system in active mode, but there were slightly more late adaptations of speed before intersections and obstacles. The test drivers were of the opinion that the system was useful, and that it would enhance safety especially in overtaking situations on motorways. The blind-spot warning was found especially useful in the overtaking process. The drivers appreciated the fact that the system did not give information all the time. The system was perceived as useful, while satisfactoriness was not statistically significantly different from zero. The findings provide important information that can be used by the system developer to improve system performance.