Estimation of the noise level produced by road traffic in roundabouts

Many studies of the environmental impact in urban areas are related to road traffic noise. The noise generated by road traffic is more disturbing near junctions, where multiple flows are intersecting. It is largely accepted that converting a cross intersection into a roundabout the noise level will decrease. This article presents a study made on a hypothetic intersection, for two different configurations: signalized cross intersection and roundabout. The traffic flow data were detailed near and inside the intersection, using traffic flow speeds measured in real conditions, for passenger cars. The analysis was made using the noise mapping software LimA. The results show that there are differences in the resulted noise levels when the intersection is detailed and these differences may affect the measures that can be undertaken by the local authorities for noise abatement. In most cases even the changes in the road network should be preceded by such analysis.