Aug 25, 2009Finding a parking spot at a hospital can be stressful for drivers anxious to enter the facility quickly, either to seek medical attention or to visit loved ones. Administrators at the Ronald Reagan UCLA Medical Center, a new hospital on the UCLA campus, hope a network of sensors used to monitor traffic in its garage will make parking faster and easier for visitors and staff members. In the long run, the data collected could also provide insights enabling the hospital to optimize the number of parking spaces allocated for workers and guests, according to David Karwaski, manager of planning and policy at UCLA's Department of Transportation.
The monitoring system comprises infrared Wireless Sensor Network Modules from National Instruments (NI), mounted at the parking garage's entrances and exits each time a car drives by. These events are collected in NI's LabVIEW software application. The data is analyzed to determine the number of available parking spots on the monitored floors, based on the total number of spaces on that floor, as well as on the number of cars each sensor detects entering or exiting.
The infrared sensors communicate using the ZigBee communication protocol, based on the IEEE 802.15.4 standard. The devices transmit their unique identification numbers, as well as the number of passing cars detected by the infrared sensors, at a low bit rate—up to 250 kilobits per second—and operate at low power to preserve battery life. The NI modules being used in the parking garage transmit at 2.4 GHz, and can operate for three years on four AA batteries when transmitting data once per minute.
The application, Karwaski says, was developed through a partnership with UCLA's Center for Embedded Networked Sensing (CENS) lab, which develops novel scientific and societal applications for sensor networks. Yeung Lam, a CENS lab programmer, designed the monitoring application and is currently deploying it in the parking garage. To date, he says, one entrance and two exit points are being monitored. But the long-term goal is to monitor not only each floor of the structure, but also each parking spot, so that the system will communicate which floors have space, as well as which specific spots are open.
At present, the collected parking data is accessible only to UCLA administrators, via a Web-based interface, but Lam says he is working with the university to design and implement a means of communicating parking availability to drivers as they approach the parking structure. The CENS lab also plans to create applications for mobile devices that would alert drivers to which parts of the garage have open parking, before they arrive at the hospital. This, he indicates, would help drivers better plan hospital visits, or potentially persuade them to use alternative transportation if the parking lot is full.
Electronically monitoring parking-lot occupancy is not new, but most systems utilize networks of wired sensors to collect and distribute information regarding availability. For an existing parking structure, such as that used by the Ronald Reagan Medical Center, the installation costs of such a system can be prohibitively expensive.
"Cutting concrete and running conduit is expensive," Karwaski says. In total, he notes, there are approximately 24,000 parking spaces on the UCLA campus, with room to add fewer than 2,000 additional spots in the future.
"There is a desire to manage the [parking] space capacity to a higher degree of granularity," Karwaski says, "so this project is a win-win because [National Instruments] is providing equipment at low cost, the CENS lab is interested in the experience of building out the system, and we in the transportation department are interested in the benefits, which are twofold. There's the customer service element—signs showing the available spaces—and the administrative benefits of having a better idea of the usage of the structure."
