Verbal Collision Avoidance Messages of Varying Perceived Urgency Reduce Crashes in High Risk Scenarios

Collision Avoidance Systems (CASs) are increasingly being installed in motor vehicles. Concurrently, verbal warnings are increasingly utilized in aviation, surface transportation, and medical environments. The current driving simulation investigation examined crash avoidance behaviors in high risk driving situations and crash rate reduction as a function of exposure to different types of verbal CAS messages. CAS messages varied in presentation level (PL) and signal word. Post-drive ratings of perceived urgency, alerting effectiveness, and annoyance were also examined. The type of CAS warning presented resulted in significant differences in appropriate crash avoidance behaviors and crash rates. In the current paradigm, the most effective CAS warnings were those of moderate PU, specifically the low PU signal word “notice” presented at high PL and the high PU signal word “danger” presented at low PL. Results are discussed in terms of their implications for CAS warning design and hazard matching applicability.