Massachusetts police started using license-plate-reading cameras in 2008, and they quickly proved their worth, says the Boston Globe. One on Sgt. Robert Griffin's Chelsea cruiser repaid its $24,000 price tag in its first 11 days on the road. Automated license plate recognition technology's popularity is exploding — seven Boston area police departments will add a combined 21 license readers in the next month alone — and with that expanded use has come debate on whether the privacy of law-abiding citizens is being violated. Precise records of where each vehicle was at a given moment can be enormously helpful in solving crimes — Fitchburg police used the technology to catch a serial flasher — but they make privacy advocates uneasy. The technology’s use is outstripping creation of rules to prevent abuses such as tracking the movements of private citizens, or monitoring who visits sensitive places such as strip clubs, union halls, or abortion clinics. A survey of police departments with automated license readers found that fewer than a third — just 17 out of 53 — have written policies, leaving the rest with no formal standards for who can see the records or how long they will be preserved. “The worst-case scenario — vast databases with records of movements of massive numbers of people — is already happening,” warns Kade Crockford of the American Civil Liberties Union, which is pushing for a state law to regulate use of license plate scanners and limit the time departments can routinely keep the electronic records to 48 hours.