Buckinghamshire CC ANPR cameras

[John Wilson]

On 7 January 2012 14:06, Roland Perry <lists at internetpolicyagency.com> wrote:
>> That's quite true but it seems clear from the Council documents that
>> they intend to hold the camera even data for some time. There are
>> perfectly legitimate reasons for this. They can, no doubt, get useful
>> information from the bulk data which would help in planning traffic
>> management.
>
>
> Unless the entire perimeter is covered (cf London Congestion Charge) then
> vehicles that 'disappear' could just as easily have taken an unmonitored
> exit. Indeed, schemes like the London CC only logs entries, and not exits, I
> thought.


It seems the Highways Agency keeps their traffic data for ever
http://www.highways.gov.uk/traffic/21002.aspx

They use the 24 bit hash value returned from the camera not the
registration number, I imagine that Bucks CC will do the same.

It appears that the hashing algorithm is a national secret
http://www.whatdotheyknow.com/request/anpr_capabilities

John Wilson