QUINCY (CBS) – South Shore police departments are now using high tech cameras capable of snapping a license plate every six seconds. But is this an invasion of privacy? The ACLU says the cameras give police too much information.

It doesn’t look very imposing, but the camera is much faster than the human eye.

A Quincy police cruiser has two of the cameras and they can read a dozen plates at once and tell the officer if the cars are legal.

“It’s an invaluable tool really,” says Lt. Jeff Burrell. “It reads the plates both coming and going. It picks up people with outstanding warrants; it picks up unregistered, uninsured stolen motor vehicles.”

But now, the ACLU wants more information about the cameras, specifically who gets recorded and how long police keep the recordings.

“It’s basically a way around the Fourth Amendment,” says Kade Crockford of the ACLU. “That requires that police get a warrant in order to search our belongings or find out where we’re going, if they’re doing it over a long period of time.”

“Realistically it’s a public way,” says Lt. Burrell. “We have no reasonable expectation of privacy, even I don’t.”