Director Sam Peckinpah allowed actor and long-time associate James Coburn to work on the movie as a second-unit director to get his DGA card, and rumor has it that Coburn actually directed some scenes when Peckinpah was "unwell."
The Mack truck in the shootout scene on the bridge was actually damaged so badly that it broke down just moments before filming the scene and had to be pushed across the bridge by a bulldozer to complete it.
The song "Old Home Fill 'Er Up and Keep On A-Truckin' Cafe" had been written in 1974 by Bill Fries (aka CW McCall) for a series of bread commercials in Nebraska, and the success of the song and commercials inspired him to write more trucking-type songs, including "Convoy" , resulting in increased interest with CB radios and trucker lingo. By the time the movie went into production in 1977, however, the trend had already faded, but that didn't stop it from being a box-office hit.
Although the movie was inspired by the 1976 song of the same title, the song really didn't have much of a plot. So after the screenplay was written, Bill Fries (aka CW McCall) recorded a new version of the song, with lyrics that incorporated the characters and events of the film. This is the version that is played during the final credits.
Sam Peckinpah was using heavy amounts of cocaine, quaaludes and vitamin shots that left him both irritable and irrational. At one point he called his nephew David E. Peckinpah, from the set, ranting that Steve McQueen and the Executive Car Leasing Co. were conspiring to kill him.
On the day the climactic funeral scene was set to film, with the cast, crew and 3,000 extras assembled, Sam Peckinpah locked himself in his trailer for 12 hours, refusing to communicate with anyone. He also fired several crew members and assistants as filming dragged on. With their director incapacitated, James Coburn and the other assistant directors essentially finished directing the film themselves.
Filming finally wrapped in early September 1977, two months behind schedule and $3,000,000 over budget. A month later, however, Sam Peckinpah was assigned to re-shoot several scenes, which he did without incident. After several months of editing, he delivered a rough cut without bothering to include the final half-hour of the movie. EMI finally lost patience with him and took over editing; yet again, Peckinpah was barred from finishing his own movie.
The famous scene where the tanker truck goes off a bridge and explodes was filmed in Needles, CA, on a one-way bridge over the Colorado River between Arizona and Needles. The Needles City Fire Department provided fire protection during this scene. The bridge was soon removed, as a new span connected the two sides of the river.
The overturning of Widow Woman's truck wasn't supposed to happen and was subsequently written into the script after it occurred. Moreover, stuntman Bob Herron was originally supposed to crash into the barn after Sheriff Lyle Wallace's car goes through the billboard.
Bill Norton's original script was a lighthearted action comedy similar to Smokey and the Bandit (1977). He pitched the script to EMI, which offered the script to Sam Peckinpah, then finishing post-production on Cross of Iron (1977). Though dubious about the project's potential, Peckinpah agreed on condition that he had complete control over the film. The studio agreed, and trouble promptly began. Peckinpah immediately started rewriting Norton's script, envisioning it as a modern-day Western with truckers fighting against crooked lawmen and unfair interstate regulations, while also adding heavy-handed political satire.
The "tank" used at the end of the movie is actually an M42 40mm Self-Propelled Anti-Aircraft Gun called a "Duster". It was used in the Korean War for anti-aircraft and in the Vietnam War for truck convoy protection duty.
Although not clear in the film, Violet the truck stop waitress is actually "Dirty" Lyle Wallace's wife. According to the commentators on the 2016 Special Edition DVD/Blu Ray, it was more implicit in the script and added to the personal tensions between Lyle and Rubber Duck, since RD is very clearly engaged in an affair with Violet. The only hints that remain in the overall film is when RD asks Violet if/when is she going to leave her "old man" (slang for "husband") when she comes back into the truck stop after the fight and lets Lyle out. He then says to her, "We'll talk about this later." Although it can be inferred from this line and the fact that she actually freed him that they are involved (in the same way she's involved with RD), there is no direct implication that they are married. It only exists in the script.
When shooting went over schedule, the production had to stop for one month due to the fact that Kris Kristofferson had touring commitments with his band. Additionally, when production resumed, Kristofferson's band played small parts as truck drivers when the production was unable to get back the actors who had been previously cast in the film due to their other commitments to other films.