Test road experiment on imminent warning rear lighting and signaling

This paper describes an experiment directed toward refinement and initial field testing of two potential countermeasures for the problem of rear-end (RE) crashes. The countermeasures consist of "imminent warning" signals intended to direct the following driver's visual glance to the lead vehicle as it brakes rapidly to a stop and for a short time thereafter.

RE crashes are the most frequently occurring type of light vehicle crash, making up at least 25% of all crashes.

A preliminary experiment was conducted to facilitate improvement of the attention-getting capability of an alternating pair of lamps. In the main experiment, an oscillating narrow beam lamp (a promising candidate from a previous experiment) and an improved alternating pair (improved as compared with that in a previous experiment) were compared with ordinary rear lighting. Seventy-two drivers were purposely distracted by in-vehicle tasks as the lead (surrogate) vehicle braked hard.

Results showed improvements of 0.25 to 0.35 s in brake activation times for the two enhanced configurations as compared with ordinary rear lighting.

The two enhanced lighting configurations show promise in reducing the number and severity of RE crashes.

The methods and results of this study can be applied to the future design and evaluation of automotive rear-end lighting designed to reduce RE crashes.