Originally Posted by
Fruit'n'nut
It's the top result on Google when you search for the relevant EEC directives; 77/212 EEC which amended 70/157 EEC, which in turn references UN/ECE Regulation 51, relating to (amongst other things) testing for manufacturer's type approval. (I've read through them this evening.) Yes, it does result in a headache!
I'll qualify my remarks by saying I'm not a traffic cop and so not trained in "roadside" testing, but
AFAIK the "approved testing method" is to follow the manufacturer's instructions for any particular testing device - so there is no single prescribed method to be quoted.
While reading around the subject, I found this link which might be interesting to you and others
http://assets.dft.gov.uk/publication...isetesting.pdf It's dated September 2010.
Interesting reading.
So at present they are using the same basic rules as the MSA as far as testing goes, or close to it.
ie 0.5m from tailpipe, level height and 45deg. Test rpm is pretty much 3750rpm
And the report deems that at present 90dB can be considered the upper limit for road vehicles. Although in their testing it is clear that a handful of factory standard vehicles have exceeded that. Most are lower though.
But it does seem to suggest that whilst cops are doing tests, they still arent usable as evidence for a prosecution, only as a guide to noise. It still falls to the cops discretion as to excessive noise. Although obviously having a high number would help them.
Last time this came up though, and cops were stopping "noisy" cars here too. Straight from the traffic cops themselves, they have no authorised equipment and have never been trained..obviously because there is no authorised equipment lol
Most of the areas where cops were targeting young motorists were normal local cops alleging complaints had been made. Unlikely as the tests were carried out in town centres nowhere near any residential.