I worked out a system two years ago for doing something like this, but with the idea of networking all of the commercial parking lots in San Francisco together,

I worked out a system two years ago for doing something like this, but with the idea of networking all of the commercial parking lots in San Francisco together, and creating algorithms & equipment to allow for either instantaneous variable-rate pricing, or to suggest parking "deals" for lot managers to announce in order to try and keep their lots full. In the end, I realized that this was price-fixing and that I would probably be sued for it. The government, however, is allowed to do things to the citizen that the citizen may not do.