Assessment of annual noise near exurbia arterial roads applying statistical processing of short term measurements

Abstract

When the annual LDEN calculated through road traffic parameters exceeds the limit value within the bounds of permissible error, in situ noise measurements should be performed for final assessment. Short-term measurements performed during a few hours cannot validate these calculations. Yearly changes in traffic parameters, such as vehicle categories and speed should be taken into account in estimating the results of noise measurements. In the described method, proportional extrapolation of the representative distribution density histogram of measured sound exposure levels for vehicle pass-bys is used for assessing the annual Z.DEN value. It includes the recalculation of the measured data on the basis of the annual whole day average. As a representative sample, the selected measurement period should meet basic ISO 1996-2:2007 requirements of at least 30 pass-bys for every vehicle category and correspond to the annual proportion between transport categories. Experiments shows, that at the distances shorter than 50 m from the road the results obtained by the suggested assessment method during only two-hour measurements are in good conformity with annual value calculations by the method Nord 1996.