Oct 12, 2007The New York State Department of Transportation (NYSDOT) is piloting a system using RFID to gather traffic data so it can apprise Long Island motorists of the time it would likely take to reach certain destination points. The information is displayed on travel time signs (TTS) operating along the Northern Parkway in Nassau and Suffolk counties. The system uses existing EZPass active RFID tags attached to vehicle windshields to clock motorists' time as they travel on the parkway. About 150,000 vehicles travel the parkway daily.
EZPass tags transmit an RF signal at 900 MHz and are commonly used by commuters to pay bridge, tunnel and parkway tolls in the New York City metropolitan area, as well as similar tolls in most northeastern states. With the new system, the unique ID numbers of EZPass tags are captured, and the time clocked, by one of 16 RFID interrogators attached to overhanging signs installed about 3 miles apart.
When the interrogators capture an EZPass ID number, the system sends that number, along with the time, via a cabled connection to Transcom, a New Jersey-based consortium of public and private entities overseeing traffic management. There, the software system (custom-built by NYSDOT) encrypts the tag data to ensure the vehicle owner's privacy.
When the vehicle passes the next reader, the tag ID number and time of day are again transmitted to Transcom, and the software compares this reading with the previous one to calculate the vehicle's speed. The system combines that speed with those of all nearby tagged vehicles and computes an average. That information, says NYSDOT spokesperson Eileen Peters, is then used to calculate the number of minutes it would take a driver to reach certain exits. The result is displayed on 12 electronic sign boards installed at various points along the parkway.
The system is part of NYSDOT's INFORM (INformation FOR Motorists) system, which includes on-ramp entrance-control lights, traffic cameras and emergency roadside service to disabled vehicles, all in an effort to maintain traffic flow on state-operated highways.
Launched on Tuesday, Oct. 9, the pilot met with an early snafu the following day, when a truck accident caused traffic to halt and the system to shut down. That, Peters says, was due to the system's inability to clock vehicles driving below 10 miles per hour. When the interrogators fail to capture a second read on a vehicle's EZ pass tag within a specified amount of time, she explains, they deactivate.
NYSDOT reset the system on Wednesday so it would remain activated as long as traffic moves at least 5 miles per hour, though the system will still not operate if traffic stops entirely. "This is just one component of the INFORM system," Peters says. She points out that in such instances, other signage continues to post warnings about traffic congestion, advising alternative routes. "So if the system goes down, you still have the signs." In the meantime, Peters states, NYSDOT engineers are working to find a solution to the problem.
The cost for this project is $450,000, most of which is related to the tag readers, which were designed and built by NYSDOT engineers. Once the pilot concludes, the transportation department expects to expand the TTS system to other New York State roadways where the heaviest congestion occurs.
