The first 250 metres must be completed at a speed of 80 to 100 meters per hour. The elevation of the race track must also decline from 110 to 125 meters during the duration of the race. A downward slope with three bends in fast succession should be included in the track design. Bobsleds have special safety features and design criteria. For example, they are not able to turn around; instead, one sled is pulled up next to the other by a team of two drivers. There is an international organization that regulates bobsleigh racing called the International Bobsleigh Federation or IBU. It was founded in 1945 and has members from all over the world. They set standards for bobsleigh equipment, rule changes, and athletics events. The IBU organizes World Championships every two years and continental championships every four years. In addition to the IBU, there are other organizations that regulate bobsleigh racing. These include the FIBT (Fédération Internationale de Bobsleigh et de Tobogganing), which sets rules for the winter Olympics, and the COC (Canadian Olympic Committee) which governs Canadian bobsleigh racing. Bobsleigh is a dangerous sport to watch because it is difficult to stop a moving sled with two people aboard. If the men don't pull their handles straight back after each curve, the nose will point down instead of up and cause the sled to crash.