Technology II: License Plate Readers

This next installment on technology’s effect on the criminal justice system analyzes license plate readers.  A license plate reader is a camera usually mounted on police cruisers, although they can be mounted anywhere.  The camera scans license plates of passing vehicles and alerts the police if there is a “hit”, a “hit” being defined as a vehicle wanted for something i.e., the vehicle was reported stolen, the vehicle was suspected in an amber alert, the vehicle was used in a robbery.

The reader allows the police to identify wanted vehicles which would otherwise go unidentified.  For example, assume a vehicle was recently reported stolen.  The report of the theft was entered into the police database, but the theft was too recent for the individual officers on patrol to know of the theft.  Absent the license plate reader, the vehicle may pass right by a police cruiser and not be detected.  The license plate reader alerts the cops that the vehicle was reported stolen.  The police then make the stop, recover the vehicle, and arrest the perpetrators.

If this was all that the license plate readers did, there would be little controversy.  After all, a license plate reader is no more than a  camera and a camera is like a set of eyes.  No one would complain if a police officer saw a vehicle in public view, remembered that it had been reported stolen, and effected a traffic stop of the vehicle.  However, each license plate scanned by the reader, not just the “hits”, is stored in a database for some period of time varying by jurisdiction. Also stored along with the plate number is the date and time the vehicle was scanned and the location where the vehicle was scanned.  This storing of data is helpful to law enforcement, for example, in locating fugitives or tracking the movements of terrorists.

People are justifiably concerned that police have access to the location of their vehicles and, consequently, their whereabouts.  Keep in mind that it is the access, not the storage, that is the problem.  Storing data that no human views does not violate anyone’s privacy.   In order to mitigate the access problems, some limits must be placed on  the who, when and where of access to the database generated by the license plate readers.

The American Civil Liberties Union has promulgated guidelines for limiting the access to license plate reader databases.  The guidelines vary from on the mark to not very well thought out.  In any event, they are a good starting point for discussion of how much access should be given to license plate reader data.  The guidelines are as follows:

1. License plate readers may be used  by law enforcement agencies only to investigate hits and in other circumstances in which law enforcement agents reasonably believe that the plate data are relevant to an ongoing criminal investigation.

There is no need for the local Barney Fife to use the license plate reader to find out where his girlfriend has been spending her time while he is on-duty.  This recommendation presents a good balance between the need to effectively investigate past and ongoing criminal activity and the need to protect the innocent motorists from invasion of their right to freedom of movement unhindered by government eyes.

2. The government must not store data about innocent people for any lengthy period.  Unless plate data has been flagged, retention periods should be measured in days or weeks, not in months and certainly not years.

This recommendation misses the mark.  As noted above, the mere storage of data without any human access violates no one’s rights.  It is only when a human looks at data placing an individual at a certain place at a certain time that privacy may be violated.  On the other hand, stored data kept for an extended period of time may prove useful in solving a cold case some years down the road. So, the balance should be struck in favor of extended periods of retention.

3. People should be able to find out if plate data of vehicles registered to them are contained in a law enforcement agency’s database.

So, if Ahmed the terrorist wants to find out if there is a record of his vehicle near the location of a recent night club bombing, he can do so.  This is not a very well thought out idea.

4.  Law enforcement agencies should not share license plate reader data with third parties that do no follow proper retention and access  principles.  They should also be transparent regarding with whom they share license plate reader data.

I would go further.  I would limit sharing of data to law enforcement agencies.  There is no need for the local government to sell this database to a marketing agency.

5.  Any entity that uses license plate readers should be required to report its usage publicly on at least an annual basis.

I do not know what this means.  The entities that use license plate readers are law enforcement agencies or, at least, they should be law enforcement agencies.  Every law enforcement agency files annual reports.  What more is needed?

There will surely be more discussion as this bit of technology becomes more prevalent.