Statistical model for traffic noise prediction in signalised roundabouts

The existing traff ic noise prediction models in road intersections relate mainly to the typical solutions of intersection geometry and traff ic organisation. There are no models for large and more complex intersections such as signalised roundabouts. This paper presents the results of studies on the development of a traff ic noise prediction model for this type of intersection. The model was developed using a multiple regression method based on the results of f ield measurements of traff ic parameters and noise levels in the vicinity of signalised roundabouts in Poland. The obtained model consists of two groups of variables affecting noise levels at the intersection. The f irst group determines in detail the inf luence of traff ic and geometry of the closest entry. The second group shows the inf luence of more distant noise sources (traff ic at the three remaining entries of the intersection) and the inf luence of the dimensions of the entire intersection. The developed model was verif ied through additional f ield measurements, as well as compared to the results of two methods of traff ic noise prediction: the French ‘NMPB-Routes-2008’ and the German ‘RLS-90’. The obtained results confirmed a higher accuracy of calculations performed using the developed model in the range of: −1.2 dB ÷ +1.0 dB, while the ‘NMPB-Routes-2008’ and ‘RLS-90’ calculate precision were respectively: −2.8 dB ÷ +1.3 dB, and +0.8 dB ÷ +5.2 dB. Therefore, the developed model allows for a more accurate prediction of noise levels in the vicinity of signalised roundabouts in a f lat terrain without buildings and noise barriers.