Brake Pulsing as Haptic Warning for an Intersection Collision Avoidance Countermeasure

Human factors issues involved in defining driver warnings for potentially hazardous situations at intersections are addressed. General issues include what information to present to drivers (warning content), when to present it (timing of warning), and how to present it (type of warning modality). The work reported is being conducted to assist in the design of a driver-vehicle interface (DVI) warning system for the Intersection Collision Avoidance Using Intelligent Vehicle Highway System Countermeasures (ICA) program. The ICA program is one of four collision avoidance system programs sponsored by the NHTSA Office of Crash Avoidance Research. Initially, the results of an on-road baseline study that examined driver behavior during approaches to intersections controlled by stop signs are reviewed with respect to the timing of driver warnings. Subsequently, haptic warning characteristics for an intersection collision avoidance system are defined, and DVI design guideline recommendations for implementing haptic warnings generated through vehicle brake pulsing are included. Vehicle brake system modifications required to achieve brake-pulsing parameters are described. Human factors test plans directed toward verification that physical properties generated through brake pulsing are readily recognized and accepted by drivers are delineated. As part of verification efforts, track tests will be performed with various intersection approach speeds and driving maneuvers. Effect of velocity on perception of haptic warning will be evaluated for ranges of magnitudes and duration of brake pulsing. The test results will support ICA test-bed development in the latter part of the ICA program.