Toward developing an approach for alerting drivers to the direction of a crash threat.

Objective: This study explored the potential for auditory and haptic spatial cuing approaches to alert drivers to the direction of a crash threat.

Background: For an automobile equipped with multiple crash avoidance systems, effective cuing of the crash threat direction may help the driver avoid the crash. Because the driver may not be looking in the direction of a visual crash alert, nonvisual crash alerts were explored as an additional means of directing attention to a potential crash situation.

Methods: In this in-traffic study, 32 drivers were asked to verbally report alert direction in the absence of any crash threats. Driver localization accuracy and response time were examined as a function of eight alert locations surrounding the vehicle and four directional alert approaches (auditory, haptic, haptic and auditory, and haptic and nondirectional auditory). The auditory directional alert approach used four speakers and broadband alert sounds, and the haptic directional alert approach used vibrations generated at various locations on the bottom of the driver's seat.

Results: Overall, relative to the auditory alert approach, the three approaches that included the haptic seat alert component reduced correct localization response times by 257 ms and increased percentage correct localization from 32% to 84%.

Conclusion: These results suggest that seat vibration alerts are a promising candidate for alerting drivers to the direction of a crash threat.

Application: These findings should facilitate developing a multimodality integrated crash alert approach for vehicles equipped with multiple crash avoidance systems.