Automated Surveillance and Police Discretion

Cyrus Farivar of Ars Technica writes that the Boston Police Department has suspended their use of license plate readers.  They note that an investigation by the Boston Globe revealed a number of holes in the program, and some strange practices.  For example, the Globe pointed out that there were instances where license plate scanners would send reports of stolen vehicles, but the police would fail to follow up on these reports:

Beyond providing snapshots of where thousands of vehicles were spotted at given moments, the data indicate that Boston police routinely failed to follow up on repeat alarms. 

Nearly 1,700 plates registered five or more scanner hits over the six-month period, most for insurance violations or unpaid traffic fines. The most-scanned plate came back as a hit for lapsed insurance more than 90 times. 

But some repeat alarms were for serious violations. One Harley Davidson motorcycle that had been reported stolen passed license plate scanners a total of 59 times between Oct. 19, 2012, and March 13, 2013. It was often recorded on sequential days or multiple times in a single day, all by the same scanner and almost always within the same half-hour span in the early evening. 

Boston police chief technical officer John Daley indicated that each of these scans prompted an e-mail alert to the department’s Stolen Car Unit, but there is no indication that the motorcycle was ever apprehended or even stopped.

Privacy advocates generally do not favor the use of automated surveillance technologies like automatic license plate scanners.  This technology, they argue, can be used to collect massive amounts of information on large numbers of people that can be stored indefinitely and used to track people's movements.

A possible silver lining to automatic surveillance practices is that evenly distributed surveillance devices could reduce police abuse of discretion in deciding whether to investigate a vehicle as stolen or in violation of the law.  Police can generally enter in any license plate information they see to their database to determine whether the vehicle they are scanning is stolen or if the registration on the vehicle is expired.

When police make these entries themselves, there is a possibility that they will enter these number in an imbalanced way.  For example, officers may, consciously or unconsciously, run license plate checks on vehicles driven by racial minorities more than they do for vehicles driven by non-minorities.  While these checks minimally intrude on those whose plates are entered into the system, it could result in disproportionate stops and enforcement of criminal laws against racial minorities, since a higher proportion of license plate checks against a certain group will likely lead to a higher proportion of that group being found in violation of the law.

Automatic scanners could partially solve this problem.  By setting up devices that automatically collect license plate information or other information, the decision of whether that information should be collected in the first place is not up to the discretion of a police officer.  While more information on more people will be collected, that information will at least be collected in a consistent manner.  One would hope that the information would be used in a consistent manner -- with uniform practices for following up on violations that are discovered.  This would seem to reduce some of the disproportionate enforcement of laws that could result from police abuse of discretion.

The flaws with the Boston surveillance program that the Globe's investigation revealed show that this hope may be misguided, or at least not guaranteed.  If police choose not to follow up on certain results, then the potential for abuse of police discretion is re-introduced into the system at a higher level.

Boston's program has been suspended for now, but it is likely that automatic surveillance will continue to be employed by more cities and law enforcement agencies.  Going forward, this story should serve as a reminder of the importance of established, consistent practices for investigating and following up on automatic surveillance reports.  And future surveillance programs will hopefully have established investigation procedures in place that will minimize the potential for abuse of discretion.