MONTGOMERY CO., Va. (WDBJ7)

UPDATE

The scene has cleared.

ORIGINAL

A tractor-trailer crash is affecting traffic on Interstate 81 North, according to the Virginia Department of Transportation.

At mile marker 124 (4 miles from Exit 128 to Route 603) a tractor-trailer crash is causing delays.

Traffic backups are about 3.5 miles long.

Check back for more information.