The sensors in Streetline's monitoring system don't have any wires, which makes installation cheaper and easier than tearing up roads to put down cables. "You can literally just stick down these speed bumps and put a system in place," says Weiss. Every four to six blocks, however, is a wired receiver--usually on a lamppost or fire hydrant--that relays the sensor data to a central server, says Reich.
Another aspect of the network is that each additional node--such as the ones that the city plans to add to parking meters to allow for remote meter paying--improves the system. "Every new application essentially strengthens the network," says Reich. "When you put sensors in parking meters, they improve the quality connection of those in the ground, so the system gets [better] quality."
Eventually, the network may include noise and air detection sensors as well. "We intend to do a nervous system for the city," says Reich.
Yossi Sheffi, director of the MIT Center for Transportation and Logistics, is skeptical that the parking sensors will be helpful, however. "The aim of the system is to make driving downtown easier and less time consuming," he says. "What we know from economics is, when we reduce the cost of any good, the use of that good goes up." More convenient parking will entice more cars downtown, Sheffi suggests: "I'm not sure that they'll get less pollution and less traffic. I think they'll achieve the exact opposite." He adds, "Cities should not make it easier to drive. They should make it easier to use alternative modes of transportation." He suggests that congestion pricing, like London's, might be better at reducing traffic.
Reich, on the other hand, suggests that the increased information will help people make better decisions, based on projections of "how much of their time is actually going to be wasted driving around." He says that the system could suggest transit alternatives at the same time that it displays parking availability, and that it will eventually be able to predict whether parking spots will be available in a particular location by the time you get there.