Demolition derby is a non-racing motorsport usually presented at county fairs and festivals. While rules vary from event to event, the typical demolition derby event consists of five or more drivers competing by deliberately ramming their vehicles into one another. The last driver whose vehicle is still operational is awarded the victory. Demolition derbies originated in the United States and quickly spread to other Western nations. For example, Australia's first demolition derby took place in January 1963. In the UK and parts of Europe, demolition derbies (sometimes called "destruction derbies") are often held at the end of a full day of banger racing.
In demolition derbies, although serious injuries are rare, they do happen. An example of a demolition derby injury is chronic whiplash pain, often characterized by migraines. Drivers are typically required to sign a waiver to release the promoter of an event from liability. At almost all derbies, attempts are made to make the event safer, all glass is removed from the vehicles, and deliberately ramming a driver's-side door area is forbidden. The driver's door is often required to be painted white with black numbers or blaze orange, or with contrasting colors, for visibility. Most demolition derbies are held on dirt tracks, or in open fields, that are usually soaked with water. This causes the competition area to become muddy, which helps to slow the vehicles. The part of the vehicle used to ram opponents varies; some drivers use both the front and rear of the vehicle to ram the other competitors, while others tend to use only the rear end of the vehicle to protect the engine compartment from damage.