The USHRA was founded as "Truck-O-Rama" in the late 1970s by Bob George, Ed Thayer, and Tony Vaccaro. By the early 1980s, the company became known as SRO Motorsports, and began promoting events under the USHRA banner. The early events focused on tractor pulling and mud bogging, and were primarily held in stadiums and arenas. Often, specialty vehicles were booked for events as intermission entertainment between competitions. In 1982, one such vehicle, Bob Chandler's Bigfoot, was booked for an event at the Pontiac Silverdome. It was that event, during which Bigfoot drove over a pair of cars in its first stadium car crush, that launched the phenomenon of monster trucks.
