Driver responses to high-mounted brake lights in actual traffic.

This study evaluated brake responses of unsuspecting drivers to brake-signal presentations using a conventional brake-lamp system with and without supplemental high-mounted brake lamp(s). The signals were presented in actual traffic during the daytime as speeds of 48 to 72 km/h. The main finding is that the signals given by the system with one or two supplemental high-mounted brake lamps were more likely to produce a brake response by a following driver. On the other hand, the reaction times of the brake responses did not vary between the systems.