I've noticed today on a couple of Surrey police cars a small black box on the roof at the back on the drivers side.
On the way home from work, I spotted a police car parked up at the road side, the bobby looked like he was looking at something on his dashboard.
Does anyone know what it is? - Is it for check the speed of passing cars?
I noticed a while ago that West Yorkshire cards have a device in the same place on the roof of their traffic cars, a bit bigger though...