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opinion | Kade Crockford and Gavi Wolfe

Don’t mine data from license plates

An automatic license plate reader camera was mounted on the back of a police cruiser in Chelsea.Suzanne Kreiter/Globe staff

Citizen outrage over government spying revelations this year has justifiably focused on the federal level, where so much of the trouble originates. Even Patriot Act lead author Representative Jim Sensenbrenner has gotten into the act, introducing the new USA Freedom Act to rein in the worst abuses of the notorious law he created.

It would be a mistake, however, to treat surveillance as just a national issue, requiring exclusively national solutions. All politics — and plenty of dangerous surveillance — is local. State and local agencies already collect troves of sensitive data about innocent people, and state lawmakers must take responsibility for protecting privacy.

The Legislature has a variety of opportunities to do so. Bills pending on Beacon Hill seek to require warrants for phone, Internet, and location tracking, to bar police surveillance of political activity, and to regulate aerial surveillance by drones in the Bay State.

One of the most urgently needed measures is the License Plate Privacy Act.


Automatic license plate readers, a powerful and popular new law enforcement technology, enable police to quickly run plates against lists of stolen cars, outstanding warrants, and expired registrations. That use of license plate readers doesn’t raise significant privacy concerns.

But, as the Globe has reported in April, police here in Massachusetts and elsewhere don’t use license plate readers only to clean up outstanding violations. They keep GPS data on every plate they read, compiling vast records on anyone who drives, detailing the movements of millions of law-abiding motorists. Just like at the National Security Agency, the default position is to collect every scrap of data.

And the information doesn’t stay local. It gets fed into regional, state, and corporate databanks, which anyone with access can use to obtain a disturbingly accurate picture of where you go and when (such as to doctor’s visits, meetings, day-care centers, etc.), even when there is no suspicion you have broken the law. All this can be done without judicial oversight. One commercial database already has 1.5 billion such records in it, and adds 70 million more each month.

We need the License Plate Privacy Act to protect both public safety and our privacy. It would spell out appropriate uses for license plate reader technology and protect motorists’ privacy by limiting the kind of information that the government can retain and the time it can hold it. License plate readers can and should be used for important real-time law enforcement purposes, such as flagging stolen cars, finding missing children, or identifying vehicles associated with some other violation of the law. But they should not record the movements of ordinary people.


Law enforcement officials have told the Globe that the state should leave oversight of this powerful tool to the police themselves — they say just trust us. The NSA scandals show what happens when we give vast powers to government agencies to spy in the dark: mission creep and the potential for serious abuses of power. We hope that police, who themselves object to being tracked as they go about their workdays, will join with the ACLU to call for sensible legislation to regulate the use of license plate readers and the collection, retention, and data-mining of our sensitive location information.

The Transportation Committee should give the License Plate Privacy Act a green light, the Legislature should pass it, and the governor should sign it into law. Let’s enable police to use this powerful tool to help protect public safety, but draw the line at amassing vast histories of where we drive and creating the conditions for the government to warrantlessly track each of us as we go about our day-to-day lives in the Cradle of Liberty.


We hope the entire Massachusetts delegation will lead Congress to pass important federal measures like the USA Freedom Act — but we can’t wait for rescue from Washington on local surveillance issues. Massachusetts legislators need to act, and passing the License Plate Privacy Act is the first step.

Kade Crockford directs the Technology for Liberty initiative at the ACLU of Massachusetts. Gavi Wolfe is the organization’s legislative counsel.