Is a Third Brake Light Required? Should You Replace Yours?

Written by

CarParts.com Research Team

Automotive and Tech Writers

Updated on March 17th, 2025

Reading Time: 2 minutes
Summary
  • The federal government has mandated third brake lights to improve brake visibility and reduce the risk of rear-end collisions.
  • Replacing a third brake light involves accessing the assembly, disconnecting the wiring harness, and replacing the faulty bulb or assembly. The replacement process will vary depending on the vehicle model.
  • Adding a third brake light involves properly wiring it to the vehicle’s brake light wire circuit and ensuring it’s properly mounted.

The federal government has required third brake lights on cars in the US since 1986 to improve the brake light’s visibility. 

What’s a Third Brake Light?

The brake light is an additional brake light that’s typically mounted high on the rear windshield of an SUV or van. On a sedan, the third brake light could be located above the trunk, at the bottom of the rear windshield.

What Are the Benefits of a Third Brake Light?

A third brake light can help ensure other drivers know when you’re braking. This is especially helpful when other vehicles obscure your brake lights due to their location alongside the tail lights

In a congested or busy highway, third brake lights can allow drivers to see braking vehicles further up the road because the lights are elevated. This gives drivers more time to anticipate and brake. 

The third brake light also only illuminates when the driver taps the brakes unlike traditional brake lights, which continuously illuminate and intensify when the brakes are applied. 

A study conducted by the National Highway Transportation Safety Administration (NHTSA), found that Center High Mount Stop Lights (CHMSL) reduced rear-end accidents by 4.4%. While this might seem like a small percentage, it saves hundreds of millions of dollars worth of damage annually.

The federal government has required third brake lights on cars in the US since 1986 to improve the brake light’s visibility. 

What’s a Third Brake Light?

The brake light is an additional brake light that’s typically mounted high on the rear windshield of an SUV or van. On a sedan, the third brake light could be located above the trunk, at the bottom of the rear windshield.

What Are the Benefits of a Third Brake Light?

A third brake light can help ensure other drivers know when you’re braking. This is especially helpful when other vehicles obscure your brake lights due to their location alongside the tail lights

In a congested or busy highway, third brake lights can allow drivers to see braking vehicles further up the road because the lights are elevated. This gives drivers more time to anticipate and brake. 

The third brake light also only illuminates when the driver taps the brakes unlike traditional brake lights, which continuously illuminate and intensify when the brakes are applied. 

A study conducted by the National Highway Transportation Safety Administration (NHTSA), found that Center High Mount Stop Lights (CHMSL) reduced rear-end accidents by 4.4%.

While this might seem like a small percentage, it saves hundreds of millions of dollars worth of damage annually.

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