We've been keeping an eye on the NZ Police trials of ANPR (automated number plate recognition - read our explanation).
The main civil liberties issue with this technology is that the system stores the time and location of the license plate check. Once enough of these systems are deployed they can be used to track people by following vehicle movements, as is being done by a number of other countries. We believe that, at a minimum, there should be some controls on how this data is stored and used, for example by having to apply for a tracking warrant.
The Police themselves have been sending out mixed messages about whether they're keeping the information and whether they'll be using it for tracking, as documented by our article. At the end of that article we said we were seeking further clarification from the Police.
Police confirm they're not keeping ANPR data for tracking
We have now received a letter (PDF) from Superintendent Carey Griffiths in which he explains:
All three patrol cars and one of the vans have the capacity to store information for up to a two or three day period depending upon operational use. In general the information is not stored for any longer than a shift period which can vary from an eight hour to a ten hour shift.
One of the [two] vans has a system known as BOSS ( Back Office System Software) and this system has the capability to store information for a longer period ... The BOSS system settings have recently been amended, and the information is now only stored for a maximum of 48 hours.
It seems clear from this that the Police will not be keeping the ANPR data.
Police believe they can't track without a warrant
Furthermore, Superintendent Griffiths goes on to say that:
Police considers that with so few cameras, the technology cannot be used to "track" vehicles. In any event, Police cannot track vehicles other than in accordance with the Search & Surveillance Act 2012.
This contrasts strongly with what the Police said in a letter from December 2011:
There is no requirement for police to apply for a warrant for any ANPR information as it is gathered in a public place.
This change in attitude is quite interesting. The Search & Surveillance Act only refers to getting a warrant for tracking when it involves the use of a tracking device (s46). We initially took this to refer to getting a warrant to allow the installation of a "bug" on the car or person to be tracked.
However, tracking device is defined as "a device that may be used to help ascertain, by electronic or other means ... the location of a thing or a person".
Could one define an ANPR system as a tracking device and would the Police then have to get a warrant to use it to track people? It seems that the Police now think it would. The same argument would also seem to apply to using mobile phones to track people.
In our opinion this interpretation would fit in both with the purpose of the Act and the requirements in a civil society for oversight of the use of this type of mass surveillance.
We're pleased that the Police are not attempting to implement the sort of pervasive people/vehicle tracking systems that are becoming popular in some overseas jurisdictions. We do not think that this sort of police state behaviour has any place in a free and democratic New Zealand.
Furthermore, after some problems with illegal surveillance in recent years, it's good to see that the Police are taking their responsibilities under the Search & Surveillance Act seriously.
We will continue to monitor the Police use of ANPR technology and look forward to receiving copies of the assessment from the Privacy Commissioner and the final Police report into their test ANPR deployment.