Ok, one last note about charging people to use the road. It's easy to draw the wrong conclusion from my posts. When people hear about these ideas, some of the ideas that pop into their heads are:
1. "Thank goodness there's a huge tax on parking in some places." Manhattan charges an unbelievable 18.375% tax on parking! (Incidentally, residents can get much of it rebated, but out-of-towners are stuck paying the whole thing. I'm not sure if this has been challenged in court yet). Anyway, taxing parking is totally backwards! What's crazy is that if there's one thing I want people to do with their cars, it's to keep them parked in garages. I don't want those things on the roads during busy times. In other words, road space during rush hour is the scarce resource that needs to be rationed via prices; room in parking garages already is rationed by the owner (since he charges for them).
2. "That's why we have a gas tax." A gas tax is not the stupidest thing on earth. As ESM has pointed out to me in the past, the government spends considerable resources keeping the waters safe for oil shipping, and it makes sense to charge the consumers of the oil. There are other externalities associated with gasoline use, so a tax might make sense. But a gas tax doesn't address the traffic problem very well. The guy driving through Nevada at 2 a.m. might be using a lot of gas but he's creating no traffic congestion. But Marginal Matt, who's driving in Manhattan rush hour traffic uses only a litle gas and creates all sorts of delays and aggravation. That's the guy you want to charge.
3. "God bless the DMV. They charge registration fees for cars." Again, cars aren't the problem; using road space when it's scarce is the problem. There may be good reasons to charge a small fee for having a car (the police now have to track it down if it's stolen, etc.), but rationing road space isn't one of them.