The purpose of this driving simulator study was to assess the influence of this onboard unit with some of the services on driver behaviour and user acceptance, by comparing driving with versus driving without the services activated.
The drive took place on a simulated typical Swedish motorway during normal traffic conditions and the stretch was about 40 km long, which resulted in a total driving time of 45-50 minutes for each driver. Each driver had to drive the same stretch twice, one time with the COOPERS information system activated and a second time with an inactive system. During each stretch, the driver was exposed to three different scenarios where the information system would warn the driver: congestion scenario, heavy fog scenario and rapid ambulance transport approaching from behind. At the end of the second drive a fourth scenario was also used, a so called ghost driver situation, where the driver meets a vehicle driving in the opposite direction in his lane on the motorway.
The simulator study, using 48 drivers, showed that the tested system had an effect of reducing the driving speed for all tested scenarios and thus a positive effect on traffic safety. Other changes in driver behaviour that can be considered beneficiary from a traffic safety perspective, like reduced longitudinal and lateral acceleration, were also observed. Overall, the mere presence of the system did not create any changes in observable driver behaviour. The presence of the system seems to have an effect when it is active in the warning phase. The study shows that when the system is active, the drivers adapt to the scenarios according to the information given through the system. The results also indicate that it would be possible to reduce driver stress in traffic by providing the driver with up-to-date information about upcoming traffic events.
M. Hjort, R. Kölbl, and S. Fuchs. Results of the coopers simulator study: A comparison of driver behaviour in different usage groups /simulation results. ITS World 2009 Stockholm.
COOPERS Joint deliverable SWP 4100 and 6500. In preparation.