Hi.I read somewhere that there was a little leeway allowed on exceeding the max speed limit.It is max speed + 10% + 2mph.This is because of the slight inaccuracy of car speedometers.I suppose for example you could travel at 35 mph in a 30 mile area. or 57mph in a 50 mile area and so on. I also believe that this is at the discretion of the traffic police involved. Is this correct or is it all "spy in the sky?". Cheers. S.O.G.
(NB: The ACPO guidelines have nothing to do with the accuracy of speedometers. The law controlling the design and construction of speedos permits them to 'over read' by a small amount but never to 'under read'. If you're pulled over for driving at 33mph in a 30mph zone, it's no good saying 'My speedo only said 30'. If it did, your true speed would have been about 26mph and 30mph. It couldn't have been 33mph).
And note the important paragraph under the table in Chris�s link:
Bear in mind that exceeding a speed limit by any amount whatsoever is an absolute offence, and a police officer is fully entitled to charge a driver for doing, say, 31 in a 30 limit outside a school at closing time, or in a busy High Street..
I think I explained this in an answer to the previous question in this section:
Thank you both for your answeres; I was always a bit sceptical about this "rule" but I know many many people who use it so I will try to educate them. Thanks again S.O.G.