Lighting question: Pulsating brake lights? 3 quicks flashes and then steady on?

[Beamercub]

I have been seeing cars with brake lights that flash 3 times then steady on? And each time the pedal is pushed they repeat the flashing.... I saw a crosstreck that had this feature on the third brake light.... Is this some type of replacement bulb? Or does some type of device get spliced on put between connections? I used to have license plate lights on my motorcycle that would do the flashing then steady on.. Any insight would be awesome. Thanks.

[upstater]

I had modulators on my motorcycle, both for brake and headlight (which is legal on a motorcycle, but not a car).

 

They do increase visibility to other motorists, the headlight modulator is the best because people think you either have an electrical issue or a few people actually 'pull over' for you, while in general I felt less people took risky left hand turns violating my right of way (which is a huge cause of accidents for motorcycle riders).