The driver, John Lewis Croy, of Union Gap, Wash., was unaware his rig was on fire until a motorist signaled him, authorities said.
``When he got out, he knew it was much too big to handle himself,'' said Montana Highway Patrolman Adam Olivas.
The fire apparently started when a tire on the tractor-trailer blew, shredding the rubber off the rim and sending a shower of sparks that ignited the refrigerator trailer's undercarriage.
Croy was hauling 78,000 pounds of cherries from Yakima bound for Illinois, was soon engulfed in flames. About half of the cherries burned or spilled onto the highway. The rest were ruined from the smoke, officials said.
Terry Ruff, chief of the volunteer fire department in Laurel, said it appeared the truck and trailer also were destroyed.
Officers shut down eastbound traffic on I-90 and one lane of westbound traffic.
