Legend has it that in 1973, a San Francisco cab driver was rear-ended for the twelfth time. In frustration, the cabbie hard-wired a truck light to his rear brake lights and placed it in his back window, effectively inventing the third brake light. Story goes, he’s never been rear-ended since.
In 1986, the Center High Mount Stop Lamp (CHMSL) – or what we all think of as the “third brake light” – was mandated for use in the United States. The theory, of course, was that a brake light placed higher and more prominently at the back of the car would help to prevent rear-end collisions. Does it work? No automobile or light duty truck manufactured after 1991 for sale in the US has been manufactured without a third brake light, so you tell us!