State police said the crash occurred when several vehicles began to swerve and brake because a ladder had fallen off a southbound truck, whose driver was not identified.
A Ford F600 flatbed truck driven by Bonney slammed into the back of a 2003 Freightliner tractor-trailer driven by Charles R. Cornelius, 44, of Munford, Tenn.
The Ford caught fire with Bonney trapped inside, according to police.
Trooper Robert Drascovic, of the Frederick barracks, and 10 passing motorists stopped their cars and rushed to the burning truck to aid Bonney, according to police. They used fire extinguishers to tamp down the flames temporarily and tied a chain to another vehicle to pull the dashboard forward, freeing the entrapped man.
"Trooper Drascovic, along with all those other people, stopped and bravely fought through flames to get this guy out of the truck," Lewis said. "Moments after they freed him, the truck pretty much just erupted into flames."
Emergency responders took Bonney to Washington County Hospital, where he was pronounced dead at approximately 5 p.m.
Traffic was backed up for miles and police called the State Highway Administration to help direct motorists through detours around the crash. Many were re-routed to U.S. 40, Lewis said.
Authorities shut down southbound I-81 for 45 minutes because the scorched truck was in the roadway, Lewis said. After I-81 reopened, only one lane was moving for more than two hours as crews cleaned up leaked fluid that had spilled onto the road, Lewis said.
Motorists reported backups of several miles along the Maryland stretch of the interstate.
No charges were filed, and the investigation was continuing, Lewis said.