Tuesday, March 1, 2011

Citation Images May Provide Indications of Errors

We previously reported on that certain versions of the Vitronic Poliscan LIDAR speed cameras, contain a recently disclosed problem which can potentially cause them to incorrectly identify which vehicle committed a speeding violation.  Poliscans are used by the SHA’s Maryland SafeZones program, which issue freeway workzone tickets, even though the Poliscan systems did not meet a requirement in state law that they have annual calibration certificates issued by an “independent calibration laboratory”

While the US versions of the systems have apparently never been tested for this possibility, there are circumstances described in the operating manual for the devices which could reveal if these errors are in fact occurring.  Citation review procedures are described on pages 95 through 102 of the manual. The manual lists several conditions which must be met in order for images to be “valid as evidence”. The Poliscan is NOT certified automatically distinguish between multiple vehicles, but rather the citation reviewers are required to verify that the correct vehicle has been selected for the violation. The Poliscan overlays a rectangular template on the citation images which a reviewer is supposed to use to verify the selection
At least one front wheel (in case of front measurement) respectively one rear wheel (in case of rear measurement) and/or the license plate of a vehicle must at least in part be visible within the template. Moreover, the lower edge of the template frame must be beneath the wheels. Otherwise, the photo must be rejected as evidence.

This particular evaluation item is repeated several times in the manual. On Page 100, it states:
Reject the photo as an evidence, if
* Neither a front wheel (in case of front measurement) nor the license plate are at least in part visible within the template,
* Neither a rear wheel (in case of rear measurement) nor the license plate are at least in part visible within the template,
* Other road users traveling on the same lane or an adjacent lane are visible within the template,

* The lower edge of the template frame is not beneath the wheels
A sample of an image which is NOT valid, merely because the template is not below the wheels is shown in the manual.
Images can also be invalid if two images are together in the template, as shown below:
While in theory all citations are reviewed, the reality is that in many cases photo citations are ‘rubber stamps’ (as proof, the many citations issued in error, and one case where in Baltimore 2000 citations were “signed” by a deceased police officer). We have seen examples where citations were issued which apparently should NOT have passed the criteria above. We would like to hear from anyone who has received a citation from one of these Poliscan cameras which may not have met the validation procedures from the manual to determine whether this is widespread, please contact us if so.  If the template is not clearly shown on the citations you can download high resolution images for citation violations from the safezones wesite.

The same type of cameras are in use in Chevy Chase Village. The village released, in response to an MPIA request, correspondence related to errors which they have seen in the past year.   Among the errors reported in late 2009 was that many citations were rejected due to the following “Site 3041: Overlay problem. Vehicles in lanes one and two were not in the overlay box. They were disapproved under “bad picture”. This occurred on Octoer 20, 24, 30, 31, Novemer 01, 03, 04, 05, 06, 07, 09, 10, 12, 13, 14, 15, 17, and 18.” This indicates that finding that it is in fact common for the device to photograph vehicles but not correctly place the template (the concern noted in the German systems, would be that they template might by chance ‘land’ on another vehicle traveling in the same direction, in a way that is indistinguishable from a legitimate violation). There are apparently also mobile Poliscan cameras in use in Bowie (who also uses ACS State and Local Solutions as their contractor) and may be in use in other jurisdictions as well.