> Kinda makes me wonder how much money is spent on road maintenance that we are not thinking as a cost while driving

Here in Japan all the highways are privatized and are supposed to be self-funded by tolls. Where I live pretty much any road trip over 45 minutes you're likely to hit a toll.

All tallied up (gas+tolls), driving 3-4 hours costs about as much as taking the 1hr 40minute bullet train (which isn't cheap - about $90 one-way). Driving only becomes economical when you're 3+ people in the car.

I imagine there would be riots in the US if the interstates all started charging tolls.