2024 Volume 45 Issue 4 Pages 184-194
Through three-dimensional wave-based numerical analysis, the propagation characteristics of road traffic noise from embankment roads were investigated, focusing on the effects of the side slope angle and height of the embankment. When the prediction plane was set as an orthogonal cross-section in the lane direction, the distribution of A-weighted sound pressure level differences between embankments with a slope and a right-angle wedge showed relatively high values in the region corresponding to the paths where diffracted sound from the edge of the embankment reflects off the ground surface, regardless of the embankment height, slope angle, and position of the prediction plane. When the embankment height and slope angle were the same, the level difference distribution was nearly the same regardless of the position of the sound source and orthogonal prediction plane. Based on these characteristics, an empirical correction formula was proposed, applicable to an arbitrary orthogonal cross-section to the embankment lane direction, representing the effect of the embankment slope angle in terms of the A-weighted sound pressure level difference. By appropriately setting the values of the coefficients required in the formula, both the maximum and average errors in the prediction plane can be reduced without significantly amplifying either of them.
