Impacts of Different Median Barrier Shapes on a Roadside Environmental Noise Screen

The aim of this article was to investigate the environmental noise effects of different median barrier shapes in the presence of a plain roadside noise barrier. A two-dimensional boundary element method was used to calculate the insertion loss of different profiled barriers over a frequency range of 50–4,000 Hz. Erecting a 1-m plain median barrier in the middle of a 40-m-wide highway has shown a considerable reduction in efficiency of a 3-m plain roadside barrier. From this point, different profiled median barriers were designed to reduce the negative effects of median barriers. It was found that sloped barriers with 10° compared with other profiled barriers have better efficiency. Comparing the overall results of tested models, the best performance improvement related to the reference barrier was seen in the barrier model “KAI” by 1.41 dB (A).