They're too big for their britches, and now they're out to change the world of fashion. They are America's truckers. During a decade of crotch-pinching rides down the interstates, they tried to wear the same jeans as movie stars. Finally they realized you can't drive all day in an 18-wheeler and still fit into a pair of Calvin Kleins.

But today the cowboys of the highway can kick up their heels again with help from Marshall Bank, 29. Bank created Long Haul jeans, the fullest-cut denims on the market—as the logo reads, "designed for the professional truck driver." Says Marshall, "People who drive trucks can't wear those jeans that cling like Saran Wrap." So he fashioned Long Haul's extra-large pockets to hold chewing tobacco, and added superwide seats and thighs. "I design," says Marshall proudly, "for the asses of the masses."

And there's money in them good ole buns. At 300 truck stops, men's and women's Long Hauls sell for $19.99, alongside T-shirts, belts and caps also made by Jonbil, Inc., where Bank is vice president—and where sales last year totaled nearly $3 million.

Bank began on the cleanup crew at Jonbil, a Chase City, Va. company owned by his dad that made generic jeans for chain stores. After one trucker complained to him that jeans generally were too tight, Bank interviewed other drivers, and a clothing line was born. Later Marshall hired 350-pound trucker Lonny T. Haul (James Weeks) as his poster boy, and Bank's buxom blond wife, Ginger, became Miss Long Haul. At this spring's Men's Fashion Association meeting in Chicago, Marshall's truckers marched their roomy posteriors down a runway before astonished fashion editors.

With planning under way for a construction workers' line called Hard Hat, Bank has moved Long Hauls into mainstream stores such as J.C. Penney and Montgomery Ward. This summer, radios will blare Bank's newest jingle: "The three best things I've ever seen—my woman, my semi and my Long Haul jeans."