You are right. I am not contesting the Highway system, which actually still seems to be a good case for Federal public spending, both because it benefits the military and because it is inter-state.
My point is entirely regarding the roads that were built out from the dense urban cores to connect with sub-urbs, and the roads built to connect sub-urbs with one another, and those inside of suburbs too. If these were paid for by those who used them (and not inner-city dwellers) then perhaps urban sprawl would not have happened, and we would have saved ourselves from a whole host of externalities we are only discovering now.
Well, they are. That's the 9/10th of a cent that drivers pay on each gallon of gas they purchase.
IMO, it should be closer to an even five cents, with half of it going to mass transit. But then I also drank milk and Pepsi mixed together when I was a kid, so I'm not exactly reliable.
There are also state gasoline taxes, vehicle weight fees (for commercial interstate trucks) registration fees, and tolls[2].
1. https://en.wikipedia.org/wiki/Highway_Trust_Fund 2. https://www.citylab.com/transportation/2017/07/us-transporta...
In the United States, it was somewhat more complex than that. The highway network was and is primarily part of the nation's military defense infrastructure, so that weapons and personnel can be moved around in a time of crisis. (Something from Germany that impressed the U.S. during WWII.)
This is why the system is named after a general who was also a president ("The Eisenhower Interstate Highway System").
It's also the reason why the rails are not usually removed from abandoned railroads anymore: So they can be rehabbed in an emergency.
There's also a lot of social studies involved, including the baby boom.
Like all large human endeavors, it's messy.
[Edit to add:]
Would private roads, paid for collectively by the developers or residents of those suburbs, have helped to alleviate or reduce the problems outlined above?
One of the many contributing factors to the U.S. Civil War was the notion that the North wanted to shed its remaining privatized roads and federalize the whole thing, while the South wanted entirely private road systems.