1 Scope
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— type approval measurements of a vehicle,
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— measurements at the manufacturing stage, and
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— measurements at official testing stations.
NOTE 1 The results obtained by this method give an objective measure of the noise emitted under the specified test conditions. It is necessary to consider the fact that the subjective appraisal of the noise annoyance of different classes of motor vehicles is not simply related to the indications of a sound measurement system. As annoyance is strongly related to personal human perception, physiological human conditions, culture and environmental conditions, there is a large variation and it is therefore not useful as a parameter to describe a specific vehicle condition.
NOTE 2 Spot checks of vehicles chosen at random are rarely made in an ideal acoustical environment. If measurements are carried out on the road in an acoustical environment which does not fulfil the requirements stated in this International Standard, the results obtained can deviate appreciably from the results obtained using the specified conditions.