 After about one year it was determined that asphalt rubber overlays resulted in up to 12 decibels of in road noise reduction, with a typical reduction of 7 to 9 decibels.Arizona has been the leader in using rubberized asphalt, but California, Florida, Texas, and South Carolina are also using asphalt rubber.Tests are currently underway in other parts of the United States to determine the durability of rubberized asphalt in northern climates, including a 1.3 mile stretch of Interstate 405 in Bellevue and Kirkland, Washington and a handful of local roads in the city of Colorado Springs, Colorado.