Even as technology moves forward and some new safety features might be added to brand new cars, there are literally millions of older vehicles that could benefit from an added safety feature that would help avoid rear end collisions and if they cannot be avoided at least reduce the severity of the impact.

The idea is to have a bulb that has some intelligence in it. The bulb would have a low cost accelerometer, as well as a microcontroller and an Osram Top Dragon or similar automotive LED.

These would be bulbs you can buy at your local auto supply store. The way I see them working is that if you brake normally, the bulb would just light up to its normal brightness. However, if you are braking hard, over a certain g-force, which means you are de-cellerating rapidly, you want to be able to warn the driver behind you that you have rapidly slowed down so they can do the same. So if you do brake hard, the bulb could either glow brighter than normal, or maybe even (depending on the country and if their laws would allow it) strobe quickly for 1 second to grab the other drivers attention to the fact you are braking hard.

By doing this, hopefully many rear end collisions could be avoided, or in some cases if the accident were to still happen, at least the impact would be less because the car behind you was able to slow down somewhat.