Privacy advocates scored a major victory in Boston this week when the city’s police department announced it would indefinitely suspend its use of automated license plate readers. The Boston Globe reports that the 14 devices currently in use let the BPD scan as many as four million vehicles a year, compiling the resulting date, time, and GPS coordinates into a massive database of private citizens’ movements around the city. Commissioner William Evans aims to review the policy surrounding license plate readers "so he knows that it’s being used effectively and that it doesn’t invade anyone’s privacy," said spokeswoman Cheryl Fiandaca.

The decision follows an inquiry by investigators at MuckRock that asked the BPD for its scan data in January, 2012. When the unredacted data was finally released in July, it revealed the precise GPS data and license plate numbers for over 40,000 different vehicles, prompting the department to freeze the program while it figures out how to proceed.

What’s particularly embarrassing for Boston Police is how ineffective the scanners appear to be at producing actual arrests. The Globe reveals that the license plate with the highest number of scans was flagged for lapsed insurance over 90 times, while a stolen Harley Davidson was spotted 59 times between October 2012 and March 2013, nearly always at the same time of day. Said the ACLU’s Kade Crockford, "you can’t help but wonder whether the real purpose is simply to collect droves of data about where innocent people are driving, in case it might be useful for investigations later."