Trusting Other Vehicles' Automatic Emergency Braking Decreases Self-Protective Driving

We focused on drivers in close proximity to vehicles with advanced driver assistance systems (ADAS). We examined whether the belief that an approaching vehicle is equipped with automatic emergency braking (AEB) influences behavior of those drivers.

In addition to benefits of ADAS, previous studies have demonstrated negative behavioral adaptation, that is, behavioral changes after introduction of ADAS, by its users. However, little is known about whether negative behavioral adaptation can occur for nonusers in close proximity to vehicles with ADAS.

Experienced (Experiment 1) and novice (Experiment 2) drivers drove a simulator vehicle without ADAS and tried to pass through intersections. We manipulated participants' belief about whether an approaching vehicle had AEB and time-to-arrival of the approaching vehicle. Participants kept constant speed or pressed the brake pedal before entering each intersection. In Experiment 2, participants rated their trust in AEB by a questionnaire after driving.

In both experiments, belief about the approaching vehicle's AEB did not influence braking probability; however, belief delayed initiation of braking. The effect of belief on braking latency was only observed when trust in AEB was higher in Experiment 2.

Negative behavioral adaptation can occur for nonusers in close proximity to users of AEB, and trust in AEB plays an important role.

When evaluating the effect of ADAS, the possible behavioral change of surrounding nonusers as well as users should be taken into account. To establish consumers' trust accurately, advertisements (e.g., TV commercials) must carefully consider their messages.