Towards an assistance strategy that reduces unnecessary collision alarms: An examination of the driver's perceived need for assistance.

The activation of present-day collision avoidance systems mainly depends on the time to collision (TTC) criterion. Such a warning strategy that is based on kinematic criteria alone often yields warning signals that drivers perceive to be unnecessary. To increase system effectiveness and user acceptance, the reduction of alert rates by tailoring system activation to drivers' needs is of great interest. The present driving simulator study investigated if drivers' perceived need for assistance in potential collision situations is primarily predicted by the TTC or by drivers' subjective hazard perception that was assumed to be influenced by the current maneuver intention. Thirty participants encountered traffic scenarios with varying levels of TTC. Each scenario was experienced with 2 different maneuver intentions to manipulate the relevance of the potential hazard. A multilevel moderated mediation analysis revealed that drivers' subjective hazard perception mediated the relationship between the TTC-based crash likelihood and drivers' perceived need for assistance. Additionally, the mediated relationship was significantly stronger when the hazard interfered with the intended maneuver. These results suggest that to appropriately adapt driver assistance to drivers' perceived needs, a warning strategy is required that considers TTC as well as drivers' maneuver intentions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).