Perceived Urgency, Alerting Effectiveness and Annoyance of Verbal Collision Avoidance System Messages

Abstract

Despite extensive examination of display parameters affecting written and nonverbal warnings, few investigators have examined presentation parameters affecting auditorially presented verbal warnings. This investigation is the first systematic examination of display parameters affecting verbal warnings that required listeners to be engaged in a contextually appropriate simultaneous task. Participants responded to verbal collision avoidance system (CAS) messages while engaged in a simultaneous simulated driving task. Perceived urgency, alerting effectiveness and annoyance ratings and behavioral reaction times were examined as a function of the signal word, CAS message, and presentation level (PL). Consistent with predictions from previous research involving written warnings, differences in the perceived urgency were observed as a function of the signal word used. PL also significantly impacted perceived urgency and alerting effectiveness. CAS messages presented at a S/N ratio of at least +4 dB resulted in high ratings of perceived urgency ratings and were responded too relatively quickly without a substantial tradeoff in increased annoyance ratings.