Both lanes of Interstate 81 south in Montgomery County have reopened after an early morning wreck near Christiansburg that sent four people to a hospital.

Virginia State Police Sgt. Bob Carpentieri said a tractor-trailer hauling steel struck a car and overturned, blocking all southbound lanes. A second tractor-trailer then hit the first one, he said. The accident occurred shortly after 5 a.m. at mile marker 116, just south of the Christiansburg and Blacksburg exits.

One passenger from the car, one person from the first tractor-trailer and two people from the second tractor-trailer were transported to Carilion New River Valley Medical Center. Carpentieri was unable to identify the victims or provide information about their conditions.

Meantime, VDOT also reports a tractor-trailer accident on U.S. 501 in Bedford County blocking northbound traffic near Short Cut Road (Virginia 651).

For updated information on road conditions, dial 511 or check www.511va.org.