NEW YORK (CBSNewYork) — When EZ Pass was first introduced, many people feared it would be used as a tracking device.

Now, that may very well be the case.

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CBS2’s Alex Denis noticed something new while driving through Manhattan; unmarked boxes affixed to dozens of traffic lights.

Experts said the boxes were quietly installed at busy intersections to collect data on cars and possibly their drivers.

A hacker who asked to remain anonymous single-handedly uncovered what the boxes were being used for when he rigged his EZ Pass tag to make a noise every time it was scanned.

While he expected the device to go off when driving through tolls, he was shocked to find the EZ pass continually made noise when he was randomly driving around the city.

“I thought that was kind of odd, because why?” he said.

“Based on a Freedom of Information Law request that the New York Civil Liberties Union made, they put together a map of where the readers are located,” AAA’s Robert Sinclair explained.

The map shows well over a hundred intersections, where cars are being scanned for a variety of details, Sinclair said.

“Information about the vehicle, the time, speed, location, that sort of thing,” he explained.

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Sinclair said there are different purposes, but mainly the tags are scanned to help monitor traffic in real time.

“If anyone has driven on the highways and seen the signs that indicate how long it might take to get to a particular destination, that’s EZ Pass information that’s being displayed,” he said.

The hacker wonders what else the seemingly personal information will be used for.

“It can know where you park, for how long,” he said, “Your day to day habits that are being tracked.”

New York City Council Member Costa Constantinides said it’s important to keep traffic moving, but not at the expense of privacy.

“I’m sure there is a shared goal of protecting civil liberties that we will certainly look into,” he said.

In the meantime, there is a way to protect yourself.

“Just put it in the bag. It will not be read if it’s inside this bag,” Sinclair said.

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After reaching out to several agencies for more clarification on how the information is being used, the New York City Department of Transportation confirmed EZ Pass readers on the street collect randomized data to help the agency monitor traffic speeds along key arteries, but would not elaborate.