Driver comprehension of multiple haptic seat alerts intended for use in an integrated collision avoidance system

Abstract

► A haptic driver seat that intuitively displays seven unique alerts was developed. ► Driver performance was examined as the number of possible alerts was increased. ► Displaying three alerts or less did not degrade driver performance. ► Distracted drivers that received alerts had faster responses to a surprise barricade. ► Alerts evoked through unique/distanced areas that map to desired responses are best. Previous research demonstrated that a haptic driver seat can effectively convey information to drivers, and suggests that it may be an ideal method for presenting haptic information because it maintains contact with the driver. The current study progresses this research by investigating whether a haptic seat can be used as the sole method for communicating multiple and meaningfully different alerts such that drivers quickly execute the correct response maneuver. An intuitive manner for presenting up to seven haptic alerts through the driver seat was developed based on driver performance with an earlier haptic seat design. Twenty-four drivers then participated in an on-road study that, through three experiments, investigated: (1) whether driver response performance to the alerts degrades as the number of possible alerts (one, three, or seven alerts) is increased, (2) whether driver response performance to the alerts degrades when alerts are presented through the same seat location, and (3) whether the haptic seat can effectively alert distracted drivers to a surprise barricade. In Experiment 1, despite drivers always making the correct response maneuver, their manual response time and verbal response accuracy significantly degraded as the number of alerts increased from three to seven. In Experiment 2, drivers’ manual response time significantly improved when alerts were presented through unique seat locations. In Experiment 3, distracted drivers that received an alert returned their gaze to the forward roadway sooner, lifted their foot up from the throttle sooner, and pressed the brake pedal sooner than distracted drivers that did not receive an alert. Overall, the study shows that confusion and delayed responses may occur when the number of possible alerts is increased, but that the information transmitted by the haptic seat alerts can be secured if the alerts are presented through unique seat locations that are spaced far apart, and map to the desired manual response. In balancing the tradeoff between communicating a multitude of information to drivers and minimizing performance decrements, a haptic seat that conveys three alerts is recommended when quick and accurate manual responses are required and additional alert modalities are not utilized. These findings are expected to inform the design of haptic driver seats.