The High Mounted Brake Lamp - The 4% Solution

The paper reviews some of the underpinnings of the research that was done that led to adoption of the high mounted brake lamp. The expected reduction in rearend collisions of 50%, attributable to the lamp, has not been realized. Most recently, a reduction of 4% was reported. This large difference between the predicted effectiveness of the safety device with its actual effect is disturbing. The paper attempts to show the reasons for the low effectiveness which include a lack of evidence for the high-mounting location, overriding an SAE standard on the intensity of high-mounted rear signal lamps and no valid theory of driver performance.