It's all about priorities: AVIATE, Navigate, Communicate.
Pilots and others with some level of emergency services / high stress career training know how to prioritize.
We need to increase standards to receive driver's licenses in America, and drill Aviate, Navigate, Communicate into their heads, and actually expose them to high-stress driving.
Speech-to-Text at its current level of development will absolutely make matters WORSE. Texting while driving makes drivers more stressed because of frustration: what's in my mind is not appearing on the screen and that means I have to try two or more times to get the message to show up correctly. This greatly increases my level of stress while driving, which is why I don't do it.
When I'm driving, if I feel like I am becoming stressed, I remove all distractions: the radio is turned off, the girlfriend has learned to be quiet, and I concentrate on the road. I wish everyone would behave this way.
One good reason why computers can do more work than people is that they never have to stop and answer the phone.