Street sensor: The circular sensor shown here, developed by Streetline, detects the presence of a car and radios that information to a centralized database via a mesh network.
The smart parking apps will allow drivers to do more than find parking. Drivers who are late returning to their spots can use the app to add time to the meter remotely. Streetline, which is providing the technology for the sensor network in L.A., is allowing garage operators to use the app to publicize discounts, and drivers can use the app to reserve a spot in a garage. Eventually local businesses could also use the app to advertise discounts or to validate parking for customers, says Zia Yusuf, CEO of Streetline.
The sensor network in San Francisco was developed by Street Smart Technologies. Workers install each hockey-puck-shaped sensor by drilling a shallow hole in the street and gluing it in place so that it is flush with the surface. In snowy areas, this low-profile design will prevent the sensors from being scraped off the roads by plows. The devices include a magnetometer (which detects the presence of a car), a processor, a battery that lasts about five years, and radios for transmitting data to a central management system via a mesh network.
Although the system is simple on a conceptual level, it’s been challenging to implement. Electromagnetic interference from buried power lines can scramble sensor measurements, so Street Smart has had to install redundant sensors at some parking spots to ensure accuracy, says Kirby Andrews, a managing agent at the company. He says everyday activities in the city will make regular maintenance a necessity: construction workers might pave over sensors, for example, or dumpsters could be pushed into parking spots. “There are a hundred things that go on that are completely unanticipated,” he says.
It’s also a challenge to communicate the new pricing schemes to drivers. Those with smart phones can access the information with the SFPark app, but Primus says some drivers, especially tourists, may never know about the different rates. He is confident, however, that even if only a relatively small number of drivers use the app, that could still make a big difference in terms of parking availability: “We only need a few drivers to change where they park to open up spaces in congested areas.”
The systems are still too new to have produced good data about their impact on traffic congestion. But San Francisco is collecting such information and will report the results as part of the requirements for its federal grant.
“Most city parking is mismanaged or not managed at all, because you can’t manage what you can’t measure,” says Donald Shoup, a professor of urban planning at UCLA whose research has shown how much drivers looking for parking contribute to congestion. “Sensing networks, by revealing what’s happening in parking spots, will change the way cities work.”