One of the promises of wireless sensor networking is its ability to add a level of sensing and control where it didn't previously exist. That's why it's so popular in building automation as well as in industrial and process monitoring, but a couple of different projects are applying it to the thorny problem of parking: both letting drivers know where parking exists and implementing pricing systems for revenue generation and urban planning.
I'll admit that most of my interest in these projects is technical; I find it interesting to see how the technology is being applied, what kinds of customization are needed for implementation, the types of information collected, and whether the systems solved the problem as intended. Several U.S.-based Smart Parking projects have been tried in recent years, one using National Instruments WSN hardware to instrument a UCLA parking garage and San Francisco's SFPark system to name but two, and New York City is now working on rolling out a parking management system as well. These aren't just research projects, either. Companies such as Libelium, Worldsensing, and Streetline all sell smart parking systems.
In addition to helping out the people valiantly trying to find parking, now that the technology exists and has (at least technically) proven itself, the cities using these systems can do some more sophisticated management of the parking sites that they control. Which means the ability to use parking management systems not only for income generation but also as an urban planning tool. To get the background on parking behavior and how urban planners use it for good or ill, I recommend reading Dave Gardetta's Los Angeles Magazine article, "Between the Lines" and, for more on the ideology of parking, I'd recommend Mike Konczal's article "A 2x2 Grid to Understanding Some of the Ideological Concerns of Privatization, Especially as it Pertains to Parking" over on Rortybomb (which is, incidentally, a fascinating economics resource).
I can't tell you how often I've heard people quote W. Edwards Deming: "You can't manage what you can't measure." It's no wonder, as it so neatly encapsulates something we know to be true. It's no surprise that this is being applied to the ever-thorny problem of parking, but I found the ways in which the data are being used noteworthy. Do you live somewhere with a Smart Parking system in place? If so, what are your thoughts about it?