FLAGSTAFF, Ariz. - The Arizona Department of Transportation is warning drivers they should expect over 4 miles of slow traffic on northbound I-17 near Munds Park.

The slow traffic is the result of a crash at milepost 321 Friday morning that killed four people, according to DPS. One other person was taken to Flagstaff Medical Center.

ADOT did not say when it expects the traffic to clear.

Information on the crash was not immediately available.