This paper presents a driving simulator study on driving behavior in a critical head-on collision scenario. The study aims at providing basic understanding of driver responses to headlight and horn warning coming from another vehicle a time critical situation. In total, 48 participants drove 30 km. During the drive participants performed a secondary task, announced by a vibration in the seat. At the time of the secondary task the own vehicle was directed into the opposing lane where oncoming simulated vehicles issued a light and/or sound warnings to get the drivers attention. An additional purpose of the study was to examine if the warning coming from the other vehicle has a different effect on persons with a hearing loss. A possible application for this type of warnings is the implementation of a system for automatic activation. Systems for automatic activation of brakes and steering are currently entering the market. These systems use proximity sensors to monitor the state of surrounding road users. Depending on the specific situation the effort/possibility to avoid or mitigate an accident may differ significantly between the principle road users of a pending collision, e.g. one road user (1) may easily avoid a collision while another (2) may not be able to do so. The only possibility for the second road user (2) to avoid a collision in such a situation is to issue a warning to the first (1), so that he/she may take evasive actions. Connecting the horn and the headlight to already existing sensor system, for automatic warning activation, is a cost effective means to provide such a warning. The warnings, could of course, also be triggered manually by the driver.

The results indicate that a driver who receives a warning from the oncoming vehicle responds faster to avoid the pending frontal collision. The most effective warning was the combination of horn and headlight. A majority of the participants where positive to the notion of an automated system to provide this type of warning (n=41). No significant difference in the behavior between the groups with and without hearing loss was found in this study.