Abstract
A total of 37 different road surface types have been tested within the project period. The road surfaces included normal dense surfaces with different chipping sizes, thin layers and single/double layer porous surfaces. On all road surfaces, CPX-measurements have been performed and SPB on a selection of the roads. In addition, texture measurements have been performed on all the dense surfaces. The performance of the test surfaces have been evaluated against a proposed reference level of SMA 0/11-types of surfaces at 50 and 80 km/h, based on CPX-measurements with the reference tyre A (Avon ZV1). The results show that new dense asphalt concrete pavements gave a tyre/road noise level (CPX) in the order of 4-8 dB(A), compared to the chosen reference level. However, after the first winter season with exposure to studded tyres, the noise levels increased with approximately 3-4 dB(A). The porous pavements tested in the project gave an initial noise reduction of 5-9 dB(A). Mainly due to wear and winter conditions, the noise reduction is only in the order of 1-2 dB(A) after 2-3 years of traffic. A detailed analysis shows that the texture is changed in a negative way in wavelengths that are important for noise generation, already after the first winter season.