I see these vehicles all the time. Today two were parked near my office (the drivers appeared to be having lunch and a chat):
However, they give me the creeps for two reasons: they are totally unmarked and they are doing automatic number plate recognition.
Since they are unmarked it's impossible to tell who's controlling them. Are they police vehicles looking for the evil-doers, or are they from the local council looking for people breaking parking laws. No idea (I think it's the latter).
ANPR creeps me out because it's part of the larger surveillance state that's evident since I returned to the UK.
The four cameras on the vehicles are marked with "PIPS Technology / A Federal Signal Company" and that appears to refer to these guys. As a geek I find the ability to spot and read multiple number plates while traveling at a relative velocity of 155 MPH very neat.
I'd just rather you didn't do that. Or if you do that please tell me why and where the data is going.