The Miami-Dade Expressway Authority (MDX) is an independent agency created in December 1994 by the State of Florida and the Miami-Dade County Commission. Since 1997 MDX has operated and maintained five expressways formerly operated by the Florida Department of Transportation (FDOT):

• Gratigny Parkway (SR 924)
• Airport Expressway (SR 112)
• Dolphin Expressway (SR 836)
• Don Shula Expressway (SR 874)
• Snapper Creek Expressway (SR 878)