PRACTICAL STATISTICS ON ROAD TRAFFIC NOISE EMISSION

EARLIER MEASUREMENTS OF ROAD TRAFFIC NOISE EMISSION SHOWED TOO LARGE DISAGREEMENTS IN THE EXTREME NOISE LEVEL AREAS (PEAK LEVEL AND BASE NOISE LEVEL) ON THE BASIS OF NORMALLY SELECTED ROUGH CLASSIFICATION IN 2.5 TO 5.0 DECIBEL STEPS. AS A RESULT OVER 50 SUPPLEMENTARY MEASUREMENTS WERE TAKEN, FOR SELECTED INFLUENCING PARAMETERS, USING AN ELECTRONIC GRADING APPARATUS WHICH PERMITTED PRECISE MEASUREMENT IN DECIBEL-STEPS ALSO IN THE REGIONS OF PEAKS AND BASE NOISE LEVELS. THE FOLLOWING DIAGRAMS DESCRIBED SEPARATELY ARE SUITABLE FOR FORECASTING APPROPRIATE AVERAGE VALUE LINES: NOISE LEVEL FREQUENCY DISTRIBUTION AT 25 METRE DISTANCES FROM THE CARRIAGEWAY CENTRE FROM THE CENTRE OF THE ADJACENT CARRIAGEWAY (MOTORWAY); NOISE LEVEL FREQUENCY DISTRIBUTIONS FOR ROAD TRAFFIC NOISES RELATED TO DISTANCE; NOISE LEVEL DECLINE AT SELECTED FREQUENCY LEVELS IN RELATION TO THE DISTANCE FROM THE ROAD CENTRELINE; THE GROUPING OF VEHICLES - NOISE LEVEL FREQUENCY DISTRIBUTION OF TRAFFIC NOISE AT DIFFERENTIAL CONTINUITY; INVERSION; NOISE LEVEL FREQUENCY DISTRIBUTIONS OF TRAFFIC NOISE ON THE EDGE OF THE CARRIAGEWAY ON NARROW CLOSELY BUILT ROADS IN RELATION TO THE CARRIAGEWAY; NOISE LEVEL FREQUENCY DISTRIBUTIONS OF TRAFFIC NOISES AT THE CENTRE OF A ROAD TUNNEL; NOISE LEVEL VARIATIONS IN RELATION TO THE DISTANCE TO THE ROAD CENTRELINE. FINALLY AN EXAMPLE IS GIVEN OF THE POSSIBLE APPLICATION OF THE DIAGRAMS SHOWN.