Effects of arousing attention on distracted driver’s following behaviour under uncertainty

This paper proposes issuing alerts to arouse driver attention when the traffic situation ahead is uncertain. Here, “uncertain” means that there exist cues suggesting something is happening in traffic ahead, but it is unclear to the driver and the driver assistance system whether an emergency situation will really occur in the near future, because traffic ahead cannot be seen directly. In such a situation, the driver has to pay attention ahead to prepare a quick response in case an emergency occurs. An experiment with a high-fidelity driving simulator was conducted to investigate the effectiveness of an attention arousing system when the driver was distracted. The results showed that the attention arousing system contributed to increasing time headway (THW) to the lead vehicle, where THW is the headway distance divided by the host vehicle speed and is often used to evaluate the rear-end collision risk. Such safety compensating behaviour was observed not only under distracted conditions, but also under non-distracted conditions. However, the compensating behaviour was not excessive under non-distracted conditions. The attention arousing was effective to maintain safety when the lead vehicle decelerated rapidly. The reaction time was long when the drivers were performing a distracting task. However, because the drivers had increased THW beforehand when conducting the distracting secondary task, the delay in reaction did not worsen the situation.