You won't be able to adjust it very high. And what is a better solution than 1 ton death traps? Is it trains? No. That would require rebuilding every city in America to be like 4 buildings and nothing else and the places where it would work already have it like new York. Is it buses? No. They are already in place and nobody uses them. So tell me, what is the actual solution besides cars?
The solution is fucking tiny cars where necessary and proper public transport - hub and spoke stuff (buses, trams) and for the big things, trains
Yes, its less convenient and requires some re-architecting of cities but if you cling to the notion that the status quo is sustainable, well, it's just not worth arguing.