I've noticed recently that the Truvelo speed cameras on my journey to work (Luton to Hatfield) have all gained an additional box on a pole adjacent to them.

From the Herts So-called safety partnership website, they're apparently due to the upgrade to digital speed cameras, which need an additional flash, which lives in the new box. And costs 11 grand, which is a lot for a slave flash unit!

Here's the link

Phil

I guess it might be an infra-red flash or similar? Truvelos are already digital, that article is talking about wet film devices (i.e. Gatso cameras)