Driver Response to Unexpected Automatic Braking/Haptic Warning While Backing

Abstract

Two studies were conducted to examine driver behavior in response to an unexpected automatic braking/haptic event while backing. One study emulated a False Positive condition (no object present in reversing path at/after braking event onset). A second study involved a True Positive condition (obstacle present at/after braking event onset). Results of the False Positive study indicated that, at braking event onset, drivers either already had their foot on the brake, or quickly placed it there. Shortly thereafter many drivers began to exhibit exploratory behavior to test the state of their vehicle, e.g. release of brake pedal, squeezing the accelerator pedal, etc. Results of the True Positive study also indicated that drivers either already had their foot on the brake or quickly placed it there. However, a higher percentage of participants held the brake pressed. Their exploratory behavior to test the state of the vehicle involved brake pedal release only. No driver pushed the accelerator pedal when an obstacle was visible in the rear-camera display. Driver eye gaze and head movements were observed for both False Positive and True Positive scenarios. Results are presented and their implications are discussed.