Safety implications of a pedestrian protection system - the driver's point of view

Pedestrians can sustain fatal injuries, even in low-speed collisions. Active pedestrian protection systems, such as an Active Bonnet, have been shown to mitigate the outcome of a collision. The study reported here aimed to discover whether such a system could have any negative impacts on the driver. One of the characteristics of the Active Bonnet is that, when deployed, it partially occludes the driver’s visual field. This driving simulator study quantified the amount of disruption to normal driving when the system is deployed, for drivers of three different heights. Curved and straight sections of road were simulated and occlusion time varied between 0.5 seconds and 4 seconds. In general, drivers’ reaction to the deployment of the bonnet was to decrease their speed; this was most noticeable for drivers at the lowest eye-height both in the straight and curved sections of road. On straight sections of road, drivers were able to maintain vehicle speed and lateral control for up to three seconds of partial occlusion of the visual field. For curved sections, this upper threshold was found to be only two seconds, reflecting the higher workload in the curved sections. When occlusion was lifted, drivers tended to then deviate in lane – a possible “panic” effect. As drivers became more familiar with the system, they applied the brakes less. In conclusion, according to the scenarios tested in this study, drivers appear to be able to cope with partial occlusions of two seconds or less and there is some evidence that a panic reaction can be lessened by familiarisation.