The aim of the present study was to investigate how quickly and efficiently distracted drivers react to four different visual warning displays intended for a Forward Collision Warning system for vehicles. The displays are the Collision Warning Head Up Display (CWHUD), the Steering Wheel Warning Display, The High Head Down Display (HHDD), and the Cluster display. The study was performed in a simulator.
Warnings were randomly presented to drivers when they were visually distracted away from the road by a traffic sign discrimination task. Brake reaction times to the different warnings were recorded. From the results of performance tests and preference ratings, the CWHUD, provided the best performance in terms of 200 ms lower reaction time and low amount of missed warnings. The average brake reaction times were significantly faster for the CWHUD warnings. There were no significant differences in reaction times among the other three warnings. One CWHUD warning was missed during the experiment, whereas 17 High Head Down Display, HHDD, warnings were missed. The CWHUD was rated first among the user preferences. The second, third and fourth choices were HHDD, Cluster Display, and Steering Wheel Warning Displays. It is concluded from the results of this study that the CWHUD was the best of the four FCW visual displays tested in the study.
The high performance and high subjective driver preference is contributed to the location color and brightness of the CWHUD providing the driver with an intuitive understanding of a forward braking vehicle.