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.