Is this likely to have been a speed trap?

[hairpin left]

I was driving back along the M48 Westbound yesterday afternoon, on the long straight stretch approaching the tolls on the old Severn bridge, and I saw (maybe too late) a dark blue saloon car parked above the inside lane on a small single track bridge that runs over the motorway. There were two people in yellow flourescent jackets behind the rear of the car, crouching or sitting behind the bridge railings. They had no headgear on, and I couldn't see any cameras, but then they do tend to be painted black and could have been in the car I suppose? Does anyone out there know whether the Police or Safety Camera Partnership who cover this area use such techniques pse and was it likely to have been a cunning low profile speed trap? There were no visible permanent or temporary camera signs on that stretch that I saw.

[droopsnoot]

Could be a traffic survey - I've seen a lot of these just recently. Plain vehicles parked on the side of the road, people in flourescent jackets with clipboards sitting on deckchairs.

[miniman]

That is a prime speed trap location. However, I have only ever seen normal camera vans on the bridges, so you might be lucky...