Seattle is launching market-based pricing for parking. This is possible now that they've installed those curbside machines that you pay to print out a parking slip for your curbside window (as opposed to the old-school parking meters for each space that took quarters). The machine adjusts pricing based on time of day and could conceivably other factors like geography, parking utilization, weather, local events, etc.

Consumers probably won't enjoy having to pay more for parking at certain times, but from an economic and environmental standpoint this makes all sorts of sense. Curbside parking has always been underpriced, overdemanded, and undersupplied. Anyone versed in microeconomics would predict higher pricing as a more optimal scenario in these cases. Variable pricing of tolls in Singapore and London has been one of the only successful means of reducing traffic there.

Over the holidays, I drove into NYC once, and at many curbs they've now installed these parking machines in the place of parking meters. I wouldn't be surprised to see variable parking pricing arrive in NYC in the next two years.

The article mentions two logical extensions of this technology, and which of the two is positive depends on your perspective:

During an interview in Seattle's Central District, Streetline rep Paul Toliver pulled out his iPad and tapped his map of Hollywood. Red and green showed filled and open spots. Parking officers can see exact spots where cars are sitting overtime, and head out to write tickets. The firm just announced an iPhone app that can send real-time price and space updates to motorists.