The Arizona Department of Transportation says the Tuesday morning crash and fire had closed westbound I-10 east of the interchange with State Route 287 but that the freeway has since re-opened.
The Pinal County Sheriff's Office said a deputy's patrol vehicle struck a tractor-trailer rig parked on the side of the highway and then caught fire.
The office says sheriff suffered only minor injuries.
Eastbound I-10 remained open.
Copyright 2015 The Associated Press modified.