The 100 cars were deployed for seven hours on a stretch of CA I-880 between Fremont and Hayward east of San Francisco. According to the event organizers, the fleet of test cars made up less than five percent of the traffic on the stretch of road at any one time. This number is based on the current potential for the market for GPS-equipped cell phones.
According to the Texas Transport Institute, Americans waste 4.2 billion hours in traffic each year, consuming an extra 2.9 billion gallons of fuel, and resulting in an estimated $78 billion in total congestion-related cost. While still in its development stages, the Mobile Century project aims to reduce these figures by tapping in to an existing and growing network of GPS-enabled mobile devices for more accurate traffic reporting.
During the field test, researchers were able to monitor the information being sent back by the traffic probes on the route on LCD monitors. The application, which was designed jointly by Nokia's Palo Alto research lab and UC Berkeley's California Center for Innovative Transportation (CCIT), shows information on current traffic speed and estimated time to certain points on the route from a preprogrammed start point.
Each car was fitted with a GPS-enabled Nokia N95 running special software. Nokia says that the GPS signals in the N95 are accurate to within 30 feet and that the system can calculate the cars' speeds to within 3mph. Data from the phones was then sent wirelessly to a server for real-time processing.
Nokia engineers explained that a key consideration in the experiment was balancing the accuracy of traffic reporting with the privacy concerns of mobile-device owners. To ensure anonymity of the data reporting, the traffic-reporting software stripped out the identity of individual phones and encrypted the data being sent. According to Nokia, a consumer application of this technology could ensure that the phones' GPS reporting capability is only activated in areas in which traffic is likely to be a concern.
Current traffic data for services such as XM NavTraffic and California's 511.org is collected using static roadside or pavement-mounted sensors and cameras, which are expensive to install and maintain. One of the main objectives of today's experiment was to compare the traffic data from the mobile Nokia devices with that from static-infrastructure reporting. To compare the two sets of data, researchers were positioned along the route to take an actual reading of traffic flow, which will then be compared against the sets of data from the two monitoring systems.