500 miles of highway/autobahn/autostrada is definitely possible, i'd say even with 2020 tech. i fully expect a long-distance self-driving passenger van/minibus service in the next 5-10 years - get on on a park&ride close to a highway, get off in the morning 500 miles away in a park&ride, take taxi/uber/train to the city center.

even better if my own car could do that - it'd make road trips on vacation so much better.