But the flip side is how much of the price of gas in the US is supplemented by the government through tax incentives and "exploration" incentives?

Further, how much is auto use supplemented by the government by using general tax revenue for highway improvement?

Sure the movement of goods on roads is great for the economy; but with individuals driving relatively empty autos for even minor errands, what has this cost the general population in general health, and the nation in pollution?