The rubberized asphalt that was a cornerstone of the Quiet Pavement Pilot Program and used to reduce road noise in the late 1990s and early 2000s is failing.
Under a 2003 mandate from then-Governor Jane Hull, the Arizona Department of Transportation used rubberized asphalt for most highway projects. The hope was the program would earn federal funding as a means of noise reduction. The Pilot Program found, however, that rubberized asphalt loses its noise reducing capacity after a few years of use, and the Federal Highway Administration ruled in 2013 that it did not meet federal standards for noise reduction.
Now, Maricopa Association of Governments data show more than 50% of Valley roadways that are paved with rubberized asphalt have exceeded their life expectancy. Money was not set aside to replace or resurface roads after 10 years of use.
Arizona is now evaluating whether to lay down more rubberized asphalt or go with a new method, such as “diamond grind” that shaves a thin layer off the top of the roadway to refresh it.
Diamond grind is still under evaluation, but some officials estimate it could cost up to $1B less than replacing rubberized asphalt. Either way, more than $1B will be needed over the next three decades to maintain Valley highways. (Source)