Road traffic is a widespread source of noise nuisance in England. The control of pass-by noise from individual road vehicles is therefore of obvious importance. This is currently achieved using the A-weighted sound pressure level and measuring the maximum sound level achieved during the full acceleration test referred to in the Department of Transport's Type Approval and Construction and Use Regulations. Limit values are in terms of maximum permissible sound levels. It has been noted that vehicles with the same sound levels can sometimes differ in terms of subjective noisiness and over the years the continued use of the maximum A-weighted sound level for control purposes has been questioned. To re-assess the suitability of this noise measure a jury experiment was conducted where subjects rated the noisiness of a range of vehicles under different operating conditions. This report describes the experimental design and analysis procedure adopted and examines the relationship between various noise measures and average subjective ratings using data from some 2250 individual vehicle pass-by events. The results indicate that A-weighted levels of noise and measures of loudness were generally superior to B and C-weighted measures.
Samenvatting