This is the problem with this kind of thing. Where is the competition? I don't blame the private companies. They are in business to make money and it's perfectly reasonable to expect they would want to reduce the competition to protect their investment. If they can't get that protection, they won't buy in. This will have to be severely regulated, so we still have government in on it.
I'd also like to know who'll be policing these "private" roads. Will the companies pony up the cash for their own police, or will government-funded police be used? This whole thing reeks when you realize there's no real privatization going on at all. But, this idea will no doubt be picked up by other states as they try to squeeze the last drops of blood from the stone.