Different note but this reminded me of an idea I was pondering one night after a bit of the devils lettuce.
Why the hell do brakes lights start red then when you brake go more red, why not lights that while accelerating are green then when foot is off the accelerator they are yellow and when braking they go red.
I can see the appeal. If I were doing this, take it a step further, and have the colours change depth of colour on a spectrum from green to red depending the amount of acceleration or braking.
However, there are a couple of reasons why not.
Your idea works as long as the driver behind is watching the back of your car all the time. If they look anywhere else, change in colour tone won’t attract the eye as effectively as brightness change at night, or no light to red light in the daytime.
Anyone with red/green colour blindness would be crashing a whole lot more often on roads, as they’d have no warning at all when you brake