What is the purpose of a center high mounted stop lamp?

The purpose of a center high mounted stop lamp, often referred to as a third brake light, is primarily to signal braking to other drivers. This additional lamp, typically positioned in a prominent location at the rear of the vehicle, enhances visibility when the brakes are applied. It provides an extra light source that alerts following vehicles to the action of slowing down or stopping, which can play a critical role in reducing rear-end collisions.

Designing vehicles with a third brake light came about in part due to the need for increased safety on the roads. Research has shown that the inclusion of this lamp noticeably improves the likelihood of being seen, especially in adverse weather conditions or at night when visibility may be compromised.

While aesthetics and compliance with regulations may play a role in vehicle design, the primary intention of the center high mounted stop lamp is functional: ensuring that the vehicle's intent to stop is communicated clearly to others on the road.