FLAGSTAFF, Ariz. -- A crash involving a tractor-trailer closed southbound Interstate 17 near Flagstaff for about three hours Friday afternoon.
The truck crashed through a guardrail at about 3 p.m. and blocked the southbound lanes about 40 miles south of Flagstaff, according to the Arizona Department of Transportation.
The cause of the crash is unknown at this time.
Traffic was stopped at State Route 179.









