The report at hand discusses the research endeavour “of reduced sound limits with the in-use sound emissions in varying traffic situations“. In the process especially noticeable peaks have been observed and their causes and effects regarding the noise situation beside roads were discussed. The influence of noticeable peaks in actual road traffic situations with typical road characteristics and traffic circumstances was gathered and the effects on prognosis-propagation calculation examined. The metrological determined influence of peaks amounts to approximately 0,5 dB(A) to 2,0 dB(A) and rises for roads with less traffic or roads with lower speed limits due to lower ground noise. Noticeable peaks arose for all road characteristics, especially in combination with commercial vehicles (pneumatic breaks, trailer/lode bed clatters/squeaks, honking), sportscars, vans, fast automobiles and motorcycles/motor scooters. The prognostic study on average leads to approximately 3,0 dB(A) or 4,5 dB(A) higher peaks (RLS-90 [4] and RLS-19 [5]). The metrological determined noticeable peaks increase the predicted peaks by 0,3 dB(A) to 0,7 dB(A). In conclusion the study shows that the influence of noticeable peaks on equivalent continuous sound pressure levels or on rating levels is minor. Nonetheless there arises a (subjective) level of disturbance caused by peaks, which if observed separately from level values cannot be depicted but as the circumstances require be purposefully determined by loudness analysis and subsequent listening tests. Based on the results of the study on different traffic conditions it is apparent, that within the assessed time intervals (day 6am-10pm an night 10pm-6am) the rating level can decrease by 1,0 to 1,5 dB(A) because of an increase in stop and go traffic. This decrease in level values only occurs with roads and road sections on which during free-flowing traffic the speed limit can actually be utilised and heightened traffic (stop and go) results in lowered speed. In the area around intersections and roundabouts such a decrease in level values can be ruled out since no relevant alteration of the average speed can be observed as deceleration and acceleration occurs throughout the different traffic situations. (Author/publisher)
Samenvatting