Gareth, old love, I'm a bit interested in this SPECS business.

About a decade back, these funny new boxes apperaed on the A14 dual carriageway between Huntingdon and Cambridge. They face towards the oncoming cars, and have a lens (presumably) and an infra-red eye. There are usually three white lines marked on the road in very close sucession.

I was given to believe that they time vehicles over a certain distance, and prosecute the speedy on that basis, as you have described above. But from Raedwulf's precise inventory, they appear to be dummies.

Also, I have seen two about a mile apart on the northbound carriageway of the A1, approaching the Gonerby Moor roundabout near Grantham, but they do not appear above either.

My interest is academic, as the fanny magnet beloved of Noreen quickly racked up 9 points for me, and now I have a nice sedate pipe-and-slippers Peugeot 406 hearse, and more importantly I re-educated myself as to how I approached driving and realised the utter stupidity of assuming journey time should be based on a world record basis.