[ThinkDifferent]

The problem, though, is that the user does not pay an incremental cost that accurately reflects his use of the system; he has no clear financial incentive to vary his travel times and/or routes in response to variations in demand.

Yes and no. When I'm sitting in rush hour traffic, I'm using more gas and wasting more time than I would be driving in off-peak hours, so there are already some incentives. Although I would agree that most motorists don't take that into account.

[Alberta's Child]

Although I would agree that most motorists don't take that into account.

That's exactly right; there is a perception among many motorists that their time isn't worth anything, which explains why people will often drive miles out of their way to save $5 on a specific item in a retail store.