Prediction
This is how it's going to happen.
1. Autodrive will be introduced as a luxury feature.
2. State governments will allow them in HOV lanes, even when occupied by one person. This is "to improve traffic flow" because the autocars can make more efficient use of space and gas by clustering themselves tightly together to reduce drag and "draft" off of each other. It'll be praised by both environmentalists and the rich.
3. States will begin setting aside Autocar lanes on the busy roads with higher speed limits. After all, reaction times being what they are, why _not_ allow autocars to go 100mph? This will intrigue the vast majority of commuters.
4. Lanes for non-autocars (and old cars that haven't been retrofitted with autocar hardware) will be dramatically reduced until in some areas of the country, the interstate system is simply not available.
5. Eventually, larger towns will become very unfriendly to non-autocars. Sure, you'll be able to still drive, but you'll need to get exceptions. Also, plan on paying a premium for the privilege. Don't worry, the US always keeps options open for its hobbyists!
And that's how it's going to go down.
