Larry Scofield, ACPA/IGGA, notes the Phoenix freeway system was overlaid with a 1 in.-thick asphalt-rubber friction course (ARFC) years ago. 

The ARFC surface is now raveling and creating damage to vehicle windshields and paint, so the Arizona DOT is considering other options. As a result, a conventional diamond ground section and a Next Generation Concrete Surface test section were constructed on SR101. The work was done by the Penhall Company, an ACPA and IGGA member.