Just paid a ticket from one yesterday. Are you sure they do a shot of the rear. They all seemed to be aimed at oncoming traffic especially the ones in the back of vans. I have heard before they shoot front and back but the way they are set up facing oncoming traffic I can't see it.
I might be wrong about the mobile ones but the fixed ones seem to. One of the first to be installed in this city used sensors under the road surface, which were installed in all four lanes. In fact, I haven't been even remotely interested in the things since then, so I'm likely to be completely wrong :)
p.s. where is home for you David? I'm in Queenstown
Christchurch. I'd like to get down to Queenstown again - its been a couple of years.
- Dave
http://www.digistar.com/~dmann/
