A regularity rally, also called time-speed-distance or TSD rally, is a type of motorsport rally with the object of driving each segment of a course in a specified time at a specified average speed. The rally is usually conducted on public roads, but sometimes includes off-road and track sections. Contestants usually compete in teams composed of an amateur driver and navigator. Teams usually start a regularity rally at fixed intervals, creating a field that is spread along the course. Origins Regularity rallying shares its origins with most types of rallying. Unlike the well-known 'special stage rallying' (which is commonly just called rallying), regularity rallying does not depend on the abilities of the driver at high-speed nor does it depend on the speed that the vehicle can achieve. For this reason, ordinary motor vehicles can be used. (Regularity rallies are commonly held for classic or even vintage cars, see below.) Regularity rallying, therefore, is a far less expensive sport and can be enjoyed by a far greater spectrum of people. With the commercialisation and increasing competitiveness of special stage rallying, many people have been financially excluded from the sport and have therefore created many cheaper alternatives. The closest motor sport to regularity rallying is road rallying. Unlike a road rally, a regularity rally focuses somewhat more on the maintenance of precise speeds and times rather than on navigation. Navigation does, however, still play an important role in regularity rallying. Characteristics A typical regularity rally may run for a few hours or it may run over a series of stages over a few days. At the start, competitors are usually briefed about the event and may be required to submit their cars for inspection. Each team is given a route schedule prior to departure. This schedule contains information that the navigator will use to try to keep to the specified route and it contains information about the designated speeds and times for each segment of the route. On some rallies, more than one type of schedule may be prepared for different types of competitors. Once a team is prepared, they will usually start the rally at a specific time unique to them. Along the route, the team will encounter marshals. The position of the marshals is usually not known to the teams. The time at which the team arrives at each marshal is recorded and used in the scoring. In some cases