High-Mounted Brake Lights and the Behavior of Following Drivers

摘要

This daytime study evaluated in-traffic responses of unsuspecting drivers to supplemental, high-mounted brake lights using two different test vehicles (compact and full size) and two different test routes (suburban and urban). The supplemental lamps were mounted just below the rear window 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 statistically among the systems tested in either of the test vehicle/test 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 statistically 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.