North Wales was until recently run by a hard-line Chief Constable, Richard Brunstrom. Brunstrom's police even prosecuted Med Hughes (his successor as ACPO Head of Road Policing) for speeding, leading to Hughes resignation. But now North Wales has a new, hopefully more enlightened Chief Constable Mark Polin. And, of course, since all speedos over-read by between 5% and 10%, at a true 30 your speedo will say you are doing between 31.5 and 33mph, so a margin of error is built in.