On other thing, he doesn’t talk about the little detail of eminent domain, which is practically required to build a highway in most of the country. Without it, nothing can get built, particularly in Texas and the Eastern half of the country where nearly all of the land is privately owned.
I guess one has to assume that he would use the state in a way similar to Kelo, to take property from reluctant owners, and hand it to a private company.
I always get annoyed at people that leave out inconvenient details of their schemes because they can lure people into thinking it’s a good idea. Take Communism. The missing detail was how to get people to work, when they received no personal benefit from it. No one bothered with that concern up front, so they got Communism, the economies tanked, and the people had to be turned into virtual (or real) slaves, to get anything at all done.
The most powerful tool a government has in its management of transportation infrastructure in the U.S. is not its powers of taxation or eminent domain, but a legal principle called "sovereign immunity." Without this immunity, a government body would be subject to massive civil lawsuits every time an accident occurs on a road in its jurisdiction. Auto accidents in the U.S. number in the millions every year, with tens of thousands of fatalities among them.
This very issue has been a subject of dispute in one of the big public-private toll road deals in recent years (I believe it involves the Indiana Turnpike). The private company that now operates the road is involved in a lawsuit related to an accident that occurred on the highway, and has been trying (unsuccessfully, so far) to get the same legal immunity from lawsuits that Indiana had when it was a state-owned and state-operated highway.
Personally, I think this problem of potentially unlimited liability is what is ultimately going to doom any large-scale privatization efforts for highways and bridges in the U.S.