I was on the M5 near Gloucester on a trip back from Plymouth this afternoon, anyway as you near Gloucester heading north they have painted chevrons on the road, there are plenty of signs on the verge saying keep your distance, and have atleast 2 chevrons between you and the car in front. Traffic was moving at 70ish, I left the gap in front to the next car of 2 chevrons, then I'm getting flashed from a 08 3 series BMW with some accountant looking guy driving about 1/4 of a chevron gap between me and him (he probally thought that if you drove a BMW the 2 chevron gap didn't apply) so I lifted off