

It’s doesn’t matter, since the absence or presence of light would still be perceived by colour blind people. It doesn’t change how they would drive, as they are already driving with the knowledge of colour blindness in mind when looking at tail lights.
But why? Again, the perception would be absence or presence of light on a standardized indicator.
FYI signal lights are much more strictly regulated in Europe, such as position, colour, shape and strength.
This study is from Austria.