Apple might be able to implement some sort of "It seems as though you are traveling in a car, we have disabled texting and driving." but then that has the obvious issue of preventing passengers from texting.

If you were to embrace the problem, whats the safest way to let people text and drive while on their phone? Something that doesn't force them to look down off the road?

Hands free voice to text sucks.

Best thing I can think of is some sort of windshield heads up display and a keyboard on your steering wheel hah