There is a similar system in Paris, if I remember correctly.

Yes, and Germany. There may be others. They (the big 'they') tried this in Nevada several years ago, but stopped after about 6 months. It seems that the last picture a number of these units took was of a pickup truck, license plate masked off, both driver and passenger wearing ski masks, with the passenger weilding a baseball bat. I guess it was pretty expensive. ;-) The ACLU was, at some point, challenging the practice of un-manned units beaming radar at every car on the road, taking pictures of those that were 'speeding'. Jim (who stands corrected, its 'CELP'.)