Automobile Rear Lights: Effects of the Number, Mounting Height, and Lateral Position on Reaction Times of following Drivers

The efficiency of 22 configurations of brake lights in actual traffic was tested in a daytime experiment by measuring reaction times of following drivers to brake signals. Analysis showed that adding supplemental (including high-mounted) lamps to conventional two-lamp configurations did not shorten reaction times. Other findings indicate that the lateral position of the lamps, the following distance, as well as the sex (6 men, 6 women) and age (19–31 yr. vs 63–71 yr.) of the 12 drivers had significant effects on reaction times, while the mounting height of the lamps did not.