A monster truck is a specialized truck with a heavy duty suspension, four-wheel steering, and oversized tires constructed for competition and entertainment uses. Originally created by modifying stock pickup trucks and sport utility vehicles (SUVs), they have evolved into purpose-built vehicles with tube-frame chassis and fiberglass bodies rather than metal. A competition monster truck is typically 12 feet (3.7 m) tall, and equipped with 66-inch (1.7 m) off-road tires.
Monster trucks developed in the late 1970s and came into the public eye in the early 1980s as side acts at popular motocross, tractor pulling, and mud bogging events, where they were used in car-crushing demonstrations. Today they are usually the main attraction with motocross, mud bogging, ATV racing, or demolition derbies as supporting events
Monster truck shows typically have two main events, a race and a freestyle competition. Races are conducted as a single-elimination tournament on short, symmetrical tracks, which may include obstacles such as junk cars or dirt mounds. The length and complexity of the track can vary with the size of the venue, with courses in indoor arenas typically being shorter with fewer obstacles.
In freestyle events, each driver puts on a performance consisting of stunts such as obstacle jumps, backflips, wheelies, and doughnuts. A panel of judges assign points to each performance and the driver with the most points is declared the winner. Historically, additional vehicles for the drivers to crush, such as motor homes and school buses, were placed on the track specifically for the freestyle event. However, incidences of debris flying into the stands and causing serious injuries have influenced most event promoters to turn away from such obstacles. Most freestyle courses now consist mostly of large mounds and ramps erected to allow the trucks to perform large jumps and wheelies upon landing. Freestyle performances have a set time limit and only one truck is allowed on the track at a time as a safety measure. Freestyle events are typically the final competition of a show, as damage to the trucks would make them unable to race