Third brake light

Yesterday I saw something on a gasoline transporter that I had not noticed before. It was a LED light that I assumed was a third brake light centered on the back of the trailer.

But it was flashing in a quick sequence. Then the truck stopped for a traffic light and the brake lights, separate from this light, came on like a regular brake light while the other light flashed.

When the truck accelerated from the stop light both the brake lights and the flashing light went off. My thought was this was a form of warning light connected to a engine compression brake or Jake brake. When the truck slows down without its chassis brakes from the compression brake this light would signal that it was slowing down. It flashed so it would be different from the regular chassis brakes being used.

Is this a good guess or is it something else?

[Dano959]

I'm not saying one way or another if you're right, but it could have been a device used to grab the attention of following vehicles. I do know that a similar device is made for motorcycles, but I believe it is wired into the already present brakelight. Also, I believe that it flashes quickly several times and then defaults to the constant on (while the brakes are engaged) of the normal brake light system.

[WERA]

I had something similar to that on my Goldwing and I've seen it on newer cars as well. It's basically just a normal thrid brake light but it flashes rather than being solid. The newer ones are programmed to flash at first then go solid after the brakes have been applied for a certain length of time. Definitely an attention getter.


Sean P. Clarke
WERA Motorcycle Roadracing