Update on automated number plate recognition (ANPR)

We recently obtained further documentation from the NZ Police about automated number plate recognition (ANPR). This includes a Police report from September 2013, the ANPR chapter from the Police internal manual and some responses to questions in our letter.

We noted the following points of interest:

  • The Police currently have 17 ANPR equipped vehicles, most of which are patrol cars that can use ANPR when mobile.
  • It costs approximately NZ$35,000 to add ANPR to a patrol car.
  • The ANPR systems are not doing live lookups against the Police databases. Rather data about vehicles of interest is uploaded each morning from a USB flash drive. This is seen as a serious shortcoming.
  • Approximately 3-4% of the cars passing an ANPR unit are “vehicles of interest”.
  • Police did a trial with the Ministry of Justice to use ANPR to identify cars of people with outstanding fines.
  • The system is used to target the expected drivers of vehicles, not just the vehicles. e.g. a car registered to a known drunk driver might be stopped.
  • Originally Police were keeping ANPR data for four months, but after discussions with the Privacy Commission dropped this down to 48 hours. They note that there are not enough ANPR equipped cars to do vehicle tracking anyway.
  • However, the manuals do talk about using this 48 hours of records to detect the location of vehicles after the fact. They give the example of a constable checking the database to see if a newly stolen car passed by one of the ANPR equipped vehicles.
  • Police documentation gives examples of using ANPR equipped vehicles to do sweeps of car parks.
  • There have been problems with the cameras misreading plates, particularly with confusion of O/Q and 1/I.
  • Police documentation points out that Police do not have a blanket power to stop any vehicle (except for administering a compulsory breath test) and that the officer must be sure that they have a legal reason to stop a vehicle of interest.


While we are not opposed to appropriate use of automated number plate recognition, we are concerned about using the system to target people and not vehicles. e.g. pulling over a vehicle because the registered owner has a drunk driving conviction. This risks unreasonable harassment of both the owner and of anyone else that they might lend the car to.

We are pleased that the Police are not using the system to set up a vehicle tracking database as we see this as a more worrying threat to civil liberties. We also note that Police statement that they believe that they need a tracking warrant under the Search & Surveillance Act to use a device (such as an ANPR database) to track vehicles.

This provides an interesting contrast to recent information from Auckland Transport about the surveillance and tracking systems they are using. We note that we currently have an outstanding LGOIMA request lodged with Auckland Transport about their surveillance plans.

However, it seems that the Police are prepared to use the 48 hours of history that they are keeping to locate vehicles after the fact, we wonder if this will be extended further in the future. This contradicts other statement and we will be asking for more information.

2 thoughts on “Update on automated number plate recognition (ANPR)”

  1. Strange you do not mention the use of ANPR by private users that have companies that monitor carpark occupants and then recheck those later to see who has not moved and then ticket them. This is in use in multiple surpermarkets in NZ.

    1. An excellent point. I believe that Sky City also uses it to help people find their cars in the car park.

      However I can’t see anything overly worrying about this use of the technology. What do you think?

Comments are closed.