[mseebach]

In the UK, speed cameras seem to be accompanied by road markings:

http://southport.qlocal.co.uk/southport/news_list/New_Speed_...

I always assumed that the radar was only for deciding to take and submit the pictures, the actual speed measurement (especially if challenged) would be done using the markings on the road.

That only requires the speed camera to have a reliable to 1/100 second clock which isn't exactly rocket science.

[mortov]

Static cameras have markings and 2 pictures are taken, normally 1/3 of a second apart. Activation is either radar or in-road inductive wiring. Neither are foolproof and pictures are supposed to be manually checked but often are not with results like this http://www.bbc.co.uk/news/uk-england-norfolk-21264281 where a claimed 50mph was actually 18 mph)

[egwor]

Someone did manage to appeal because they'd incorrectly painted the markings too close together. You have to check everything ! :D