ALBANY - E-ZPass, the popular electronic system that allows motorists to zip through toll booths, is being tested as a way to clear traffic jams.

Portable roadside E-ZPass readers are stationed this week outside the New York State Fair near Syracuse to help track the flow of thousands of vehicles. Researchers say the information gleaned from passing cars - which they stress is encrypted and anonymous - will help engineers figure out ways to redirect traffic to less congested routes in the future.

The six readers arrayed along Interstate 690 and other access routes to the fair keep track of the time it takes for vehicles with E-ZPass tags to travel from point to point. In effect, cars become probes.

“Any time a vehicle passes a pair of readers, you can get that travel time rather than just get a spot speed,” said Jeff Wojtowicz, a research engineer at Rensselaer Polytechnic Institute, which is directing the study.

Researchers say more than a quarter of the cars headed to the fair have an E-ZPass, which is enough to help provide accurate traffic information for I-690, which is under heavy construction.

Based on data from E-ZPass readers and other types of traffic trackers, officials could create detours to keep traffic flowing smoothly, said Al Wallace of RPI's Center for Infrastructure and Transportation Studies.

Information collected this year will help the state Department of Transportation ease congestion for the fair next summer. But Wallace said such system could also provide real-time relief.

“We think it's major impact is going to be for any type of special event, whether it's construction or a state fair or something at Saratoga,” he said.

E-Z Pass has been used in a similar manner by the Thruway Authority near the Tappan Zee bridge north of New York City since 1994. The authority uses readers to keep track of travel times approaching the bridge and advises commuters via electronic signs and radio if traffic is heavy.

RPI said the data they receive is coded and they could not match it with specific tagholders even if they wanted to. But the fact that the data was being collected was enough to raise concern.

New York Civil Liberties Union Executive Director Donna Lieberman said that while it's fine to take advantage of the latest technology to solve problems, the information should be erased as soon as its no longer useful to make sure it's not misused.

“This is a case, once again, where technology can be a tremendous help, and it also poses risks,” she said. Thruway spokeswoman Sarah Kampf said that when measuring traffic flow, the authority does not keep information on the anonymous, individual tagholders, only the aggregate data.