sure someone must have said this but the kind that only seem to be able to do 40mph.
right up close behind you at 30.. or driving infuriatingly slowly anywhere else xD
or, the other day i had someone on a 60mph road drive SO close behind me i couldn't see his headlights. I was doing 60, but my main query is that the road was EMPTY in the other direction, so he could have very easily overtook me if he was so desperate to go racing off..
this seriously confused me!