If we add the gas taxes, traffic fines, car registration, taxes on new/used automobiles, and taxes on all car-related items and services then subtract the "big digs" of the world and the prevailing wage used to build them, highways still don't pay for themselves? I find that hard to believe. Sounds like commie propaganda to me.
Even if our highway system is subsidized, It's pretty obvious that HSR will have to be subsidized too. My question is why add another money pit to the transportation system? I'd rather spend that money on what already exists, like light rail. Relieving congestion within a region is more important to me.
Though I'm a libertarian, I can accept government paid infrastructure. However, I still think it would be better (in the end) if government pulled back and allowed demand for private road and rail construction to grow.