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.
Tail lights being red is fine if you live with the most common forms of colorblindness which fall into what we call “red-green colorblind.” It is still a different color than headlights.
Now put those same red-green lights on the front, and we have a problem.
We use plenty of biodegradable plastics. They’re not always the correct solution. You wouldn’t want an airplane biodegrading, for example.