Um, if you live outside of a few central cities, I hope you’re on good terms with your local farmer…
Most goods in this country are moved via truck, largely from Los Angeles/Long Beach. Additionally, as I’m sure you’ll note, most food is moved via truck from rural areas to the rest of the country.
So, I will take a step ahead of you and assume your statement applies only to civilian driving, not industrial, military, or commercial.
First of all, that whole Los Angeles place? San Diego? Probably Miami? Wouldn’t exist anymore. While I assume that some of the larger, denser cities could resort to mass bike and mass transit options…
Well, I have this theory of “1”. “1” is the furthest distance you travel daily - the distance to work, the distance to college, etc. Every other distance is relative to “1” - if a grocery store is farther away than “1”, it is “too far away”, and if closer, is “I live by it.” I developed this theory as a pedestrian/mass transit rider, going from Oakland/Berkeley to San Francisco. I noticed that my previous “1” of maybe 4-5 blocks in Berkeley turned into a 45 minute train ride and two 10 minute walks. Suddenly, I was much more willing to go further distances.
Now, applying that theorum, “1” would, overnight, become a very short distance for millions of Americans.
Cities would shrink, basically. Their carrying capacity would become smaller. If you’ve ever played city-building strategy games, like Caesar, you’d know that the life of a city is based on proximity to goods and services. In a larger, denser city, one market serves more people. When they have to walk too far to the next market, they just get pissed off or move. And lower your City Rating, which is a bad thing.
We would certainly be traveling less.
Well, the general gist is, regionalization. You’d probably see local politics being more important again 
In general, it would cripple industry, destroy society, put a chokehold on the economy, devastate cities…
Probably would be a lot less pollution, though.