Rallies are non-speed skill events which are conducted on public roads – at or below legal speeds. The types of rallies put on by SCCA range from fun rallies (gimmick type) to time-speed-distance (TSD) rallies. The most popular and well-known type of rally is the TSD or time-speed-distance rally. In TSD rallies, a driver/navigator team tests it ability to follow a given route at prescribed speeds. Each team is scored on its ability to arrive at unknown control points neither early nor late, but exactly on time. Teams are usually separated into one of two categories of competition based on the equipment they have to aid them in accurately following the designated route at precisely the right time and/or speed. One category is for the teams that depend only on the basic essentials such as the family car, watch, and rally tables. The other category is for the devoted TSD rallyist who uses sophisticated electronic equipment such as special odometers that read to the nearest hundredth of a mile and electronic computers which automatically calculate speed and provide a continuous indication if you are ahead, behind, or on time.