HIGH-MOUNTED BRAKE LIGHTS AND THE BEHAVIOR OF FOLLOWING DRIVERS

Abstract

16. A~S~~OC~ This daytime study evaluated in-traffic responses of unsuspecting drivers to supplemental , high-mounted brake 1 ights using two different test vehlicles (compact and full s ize) and two different test routes (suburban and urban). The supplemental lamps were mounted just below the rear winidow or at roof level. Measures were taken of brake-response and vehicle speed-change frequencies, and of the corresponding reaction times. (The speed changes were measured by radar.) The following main results were obtained: The frequency of brake responses and of speed changes did not differ statis tical ly among the systems tested in either of the test vehicleltest route combinations. Brake-reaction times did not vary among the systems tested for any of the test vehicle/test route combinations. Speed-change reaction times also did not vary among the systems tested for any of the test vehicle/ test route combinations with the exception of the compact vehicle/urban route combination: Here, a system with a single, supplemental lamp, center-mounted just below the rear window , was associated with s tati sti cally shorter reaction times than the control system. The relation of the present findings to previous behavioral and accident studies of the efficacy of high-mounted brake lights is discussed.