I hope this is a wind up!

I can see both sides of the argument but surely 30mph means 30mph so why turm a blind eye to exceeding it?

The site speed limit of 5mph means just that and we complain about people exceeding it so where’s the difference?

The margins were put in place to allow for calibration errors on Speedometers. -------- IMO those margins should remain.  Sounds like good  quality investigative reporting is still present on the quality newspapers, bringing proposals like this to the discerning public's attention. 

K 

Mmm, a bit like you and VW in a way, K.

Are speedos that accurate TW, that’s the point. We know that they are not! I can see the public travelling around at 5mph below the speed limit just in case. I agree that walking pace should remain on sites re children etc but 1mph? 

I told you I could see both sides of the argument but there’s no way I’m going to condone lawbreaking, Merve.

New car speedo's are not accurate which is why new police cars have to them calibrated, fact.  My own car under reads by about 3 mph at 30 to more than 6 mph at 70 when compared with roadside warning signs and GPS. 

Just a another case of a Chief Plod talking rubbish In my opinion.  

He has definitely said it at a recent conference that he thinks the 10% margin over the speed limit should be scraped. Obviously no one would condone breaking the speed limit but I would want reassurance that any equipment used to measure the speed of a vehicle was 100% accurate but could anyone actually give that guarantee? If not it can't be done. I assume the reason for the 10% margin is because accuracy cannot be guaranteed? There would have to be some proof that being within that 10% margin was actually responsible for more accidents which I somehow doubt. 

David

Some motorists believe that the law does not apply to them so instead of being under 30 to be sure they will do 33 and claim the 10%

"The Motor Vehicles (Approval) Regulations 2001 permits single vehicles to be approved. As with the UNECE regulation and the EC Directives, the speedometer must never show an indicated speed less than the actual speed."

So yes, remove the margin.👍

A modern speedo is manufactured to only overead, if it undereads then its broke.

Some margin is necessary. I generally rely on satnav as speedo neither well placed or easy to read at an angle near middle of dash in the X-Trail. When driving the Yaris it has a digital speedo and in either case you do not know you are exceeding 30 until it actually shows 31.

No cruise control on Yaris and so if trying to maintain 30mph it is easy to vary between 28 and 30 or so and 32 say, particularly with gradient changes, unless watching speedo instead of road.