I've spent most of my life in places where I drive quite a ways daily, in TX, NM, and now CA, and I'm still not sure what the answer is for the road use tax. A mileage tax makes the most sense to me, because it affects people in electric and hybrid as well as gas vehicles. But it is regressive, and people who pay less for housing outside the city then have to pay more to commute. Here in the Los Angeles area, housing is so expensive that working class people often have to travel long distances to work.
One thing that always surprises me, is how few people here carpool.