VDOT says the crash has been cleared.
VDOT says an accident involving a tractor trailer has both southbound lanes of Interstate 81 blocked, about a mile north of Buchanan in Botetourt County. VDOT says the tractor trailer has flipped.
Traffic is backed up about 3.5 miles as of 11:11 a.m.
Southbound traffic is being detoured off of I-81 south at the Arcadia exit (Exit 175) and back onto I-81 south at Exit 162, south of Buchanan.
VDOT did not have an estimated time for when I-81 will re-open.