Quieter Hot-Mix Asphalt Pavements in Washington State

Historically, traffic noise has been reduced through the construction of noise walls and berms, which can be costly (US$2 to $3 million per kilometer in Washington State). Open-graded friction courses (OGFCs) have been found to reduce tire–pavement-related noise. However, OGFC pavement surface lives of less than 10 years, and as short as 4 years, have occurred in Washington State. The primary reason for early failure is surface wear caused by studded tires. In 2006, the Washington State Department of Transportation (WSDOT) placed the first of three test sections (the second test section was placed in 2007 and the third will be placed in 2009) to evaluate noise reduction qualities and pavement performance with the Arizona Department of Transportation (Arizona DOT) asphalt rubber–asphalt concrete friction course, Arizona DOT asphalt concrete friction course modified with styrene–butadiene–styrene, and a standard WSDOT 12.5-mm dense-graded hot-mix asphalt. This paper focuses on pavement surface life and quantifies the reduction and sustainability of tire–pavement-related noise for the project placed in 2006. Initial findings suggest that the OGFC noise reduction benefits quickly diminish as a result of increased surface wear caused by studded tires.