In the 1975 trucker song “Convoy,” a voice can be heard on a CB radio. “What’s your 20?” the voice asks, code for “what’s your location.” The answer comes back: “Omaha.”

Of course it did. The song itself was from Omaha. And while there were a lot of trucker songs in the 1970s, few could boast the sort of strange backstory “Convoy” could, and none could look to the sort of future the song had.

First, the backstory: “Convoy” was the product of a successful advertising campaign. The product was Old Home Bread, the advertising agency was Omaha’s Bozell & Jacobs. They conceived of a series of ads featuring a truck driver delivering bread to a diner waitress. The waitress was named Mavis Davis. The truck driver was C.W. McCall.

The campaign proved to be popular—so much so that McCall broke off to be an independent character, releasing a number of recordings. The lyrics and singing voice for McCall belonged to Bill Fries, while the songs were written by Chip Davis. Fries later became mayor of Ouray, Colorado, while Davis founded Mannheim Steamroller.

“I said one time that I would never live in Nebraska and I would never write country music,” Davis explains. “I guess we see how that all worked out. My love of music was really in the classical area but my good fortune—and I mean fortune—came by way of writing “Convoy.””

The song tells the story of a lawbreaking, protesting collection of truckers riding cross-country together as a miles-long ribbon of working class antiheroes communicating on CB radios. It became a crossover hit, spending six weeks in the number one slot on the country charts and a week as number one on the pop charts.

As a result, “Convoy” joined the ranks of country songs in the ‘70s that became films along with “Harper Valley PTA,” “Ode to Billy Joe,” and “Take This Job and Shove It.” The film version began shooting in 1977 and boasted an impressive collection of talent. Country legend Kris Kristofferson was cast in the lead along with Oscar-nominated Ali MacGraw and character actor Burt Young. Oscar-winner Ernest Borgnine was the villainous county sheriff determined to break up the I-can’t-drive-55 convoy.

“Convoy” was a pop culture sensation and helped spawn an era when CB radios were all but ubiquitous in every vehicle, even your mom’s station wagon, but Davis and Mannheim Steamroller are also celebrating a pair of even more notable milestones.

This summer, public television stations throughout the U.S. will air Mannheim Steamroller 30/40 Live. The concert special marks two anniversaries for the hugely successful act; their debut album, Fresh Aire, was released four decades ago, followed ten years later by the release of Mannheim Steamroller Christmas, their first holiday album, to huge success.

‘“Convoy’ and the other 12 hits we had,” Davis explains, “ultimately funded Mannheim Steamroller and [record label] American Gramaphone. I’m a lucky guy. Going from a semi to a steamroller wasn’t all that difficult.”