Model-based approach for acoustic pavement characterization

The CPX method for pavement characterization is standardized at speeds of 50 and 80 km/h, but its applicability<br />on roads with speed limits of 30 km/h remains uncertain. In a research project, a model-based approach was investigated to estimate acoustic pavement quality from asphalt's sound absorption, airflow resistance, and surface texture. These three parameters were measured in situ on multiple road sections with varying acoustic characteristics, followed by local SPB measurements to derive spectral pavement corrections for the Swiss road traffic noise emission model, sonROAD18. Correlations were observed between surface texture levels and these pavement corrections, partially explaining how texture influences acoustic performance and pavement noise reduction. This work indicates that predictions based on a combination of sound absorption, airflow resistance, and surface texture may offer improved accuracy compared to the traditional CPX method. Except airflow resistance, measurement of the three parameters does not necessarily require a static setup, thus allowing for dynamic measurement approaches. The current dataset needs expansion with other pavement types and the models will be refined to support more comprehensive acoustic pavement quality assessments at speeds below 50 km/h.