On June 9, 2008, the Clayton Bypass opened, redirecting US 70 onto I-40 between exits 306 to 309 and then on a new four-lane freeway bypass south of Clayton. Planning for the bypass began in 1991, but construction did not start until 2005 because of several delays regarding the Dwarf wedgemussel, an endangered species, habitat in the area. Originally scheduled for completion in June 2009, a severe drought in 2007–2008 allowed construction to proceed more rapidly than anticipated. NCDOT was given the approval by AASHTO to officially designate US 70 along the bypass on May 6, 2008, with the former alignment becoming an extension of US 70 Bus. Compared to the former alignment through Clayton, the bypass is estimated to cut fifteen minutes of travel time for drivers traveling between Raleigh and eastern North Carolina.