BMX racing is a type of off-road bicycle racing. The format of BMX was derived from motocross racing. BMX bicycle races are sprint races on purpose-built off-road single-lap race tracks. The track usually consists of a starting gate for up to eight racers, a groomed, serpentine, dirt race course made of various jumps and rollers and a finish line. The course is usually about 15 feet (4.6 m) wide and has large banked corners, which are angled inward, that help the riders maintain speed. The sport of BMX racing is facilitated by a number of regional and international sanctioning bodies. They provide rules for sanctioning the conduct of the flying, specify age group and skill-level classifications among the racers, and maintain some kind of points-accumulation system over the racing season. The sport is very family oriented and largely participant-driven, with riders ranging in age from 2 to 70, and over.