The land speed records are speed runs for a measured distance to see and document who can go the fastest average speed when traveling down the course and back. Specially-prepared vehicles of all makes and styles operating on different fuels and with various-sized engines race against the clock on the salt surface, attempting to go faster than any other comparable vehicle has previously gone. In some instances, companies such as the Goodyear Tire & Rubber Company® create special tires to assist vehicles in breaking the speed records while providing traction, safety and vehicle control.
When attempting to set land speed records, the area known as the Great Salt Flats of Utah in the western United States is the place to be. This area, often referred to as Bonneville or the Bonneville Flats, hosts the event to set land speed records yearly for nearly any type of engine-powered vehicle imaginable. The land speed records are divided into many different classes, from wheel-driven to rocket- or jet-powered as well as car and motorcycle groups; many sub-groups exist in each category. The vehicles are allowed to begin the speed attempt from a rolling start due, in part, to the inability of most tires to grip the salt when power is applied. Drivers must use extreme caution when attempting to set land speed records, and several drivers have been killed due to crashes while racing on the salt flats.
The official method of setting land speed records is to make two runs or passes down a measured speed course and average the total speed of both runs. Each run must be made without repairing the vehicle between runs, and the driver must complete the second pass within an hour of making the first pass. In order to officially qualify for setting land speed records, the average speed of the two passes must surpass the existing record run by 1 percent. The reason for running both ways on the racing course is to even out the advantage of driving with a tailwind.
The original land speed records were all set by wheel-driven vehicles until the early 1960s, when the three-wheeled Spirit of America, a rocket-propelled vehicle, created controversy by not being wheel-driven. Since that time, separate classes for wheel- and rocket- or jet-powered vehicles were created. Since the introduction of the class, the outright land speed records have been held by rocket or jet engine vehicles.