> I don't think we could go down to zero cars any time soon

Of course I have no idea the specifics of where you live, but I think many suburbs could make this possible within 5-10 years by:

-zoning an area to be the suburb's "downtown", i.e. a few blocks of small apartment buildings with ground floor retail including a grocery store and restaurants

-building high-quality bike lanes to get to the new downtown

-subsidizing a service like car2go to make it easy to access cars on-demand when you need to go somewhere farther