I'm on the GW Bridge the other day in stop-and-go traffic. The pace picked up a little bit, and I am following a late model BMW 535. He brakes suddenly, and I just barely miss rear-ending him. The only reason I didn't? He had a secondary set of adaptive brake lights, a brighter, secondary set of brake lights that illuminated to let me know he was braking hard.
The implementation seems simple enough; depress the brakes hard enough or panic stop, and an extra, brighter LED / bulb is activated to warn the driver behind you. The result is saving a few precious milliseconds that could be the difference between a short stop and a costly insurance deductible.
So the question is, why doesn't this kind of innovation, and other ideas make their way into more cars if it's clearly safer? For example, many VW Jettas have a feature that blink the brake lights when at a standstill, so you don't get rear ended at a traffic light. Recent Ford Mustang models also have sequential tail lights that indicate the direction of turn, which is also helpful.
In the last 50 years, the biggest innovation in brake lights has been the high-mount stoplight, which was so effective it was mandated into Federal law. There are a lot of NHTSA regulations governing the illumination of brake lights, but for now the luxury car makers like BMW, Mercedes and Audi are leading the way. It will be interesting to see where this technology goes.