for amateurs to try racing and is also a fully-fledged international sport in its own right. A large proportion of professional racing drivers began in karts, often from a very young age, such as Michael Schumacher and Fernando Alonso. Several former motorcycle champions have also taken up the sport, notably Wayne Rainey, who was paralysed in a racing accident and now races a hand-controlled kart. As one of the cheapest ways to race, karting is seeing its popularity grow worldwide. Despite their diminutive size, karts of the most powerful class, superkart (assuming a weight of 205 kg (452 lb), and a power output of 100 hp (75 kW)), can have a power-to-weight ratio (including the driver) of 490 hp/tonne (0.22 hp/lb). Without the driver, this figure doubles, to almost 980 hp/tonne (0.44 hp/lb). Historical racing Historic motorsport or vintage motorsport uses vehicles limited to a particular era. Only safety precautions are modernized in these hobbyist races. A historical event can be of various types of motorsport disciplines, from road racing to rallying. Because it is based on a particular era it is more hobbyist-oriented, reducing corporate sponsorship. The only modern equipment used is related to safety and timing. A historical event can be of a number of different motorsport disciplines. Some of the most famous events include the Goodwood Festival of Speed and Goodwood Revival in Britain and Monterey Historic in the United States. Championships range from "grass root" Austin Seven racing to the FIA Thoroughbred Grand Prix Championship for classic Formula One chassis. While there are several professional teams and drivers in historical racing, this branch of auto sport tends to be contested by wealthy car owners and is thus more amateur and less competitive in its approach. Other categories Use of flags In many types of auto races, particularly those held on closed courses, flags are displayed to indicate the general status of the track and to communicate instructions to competitors. While individual series have different rules, and the flags have changed from the first years (e.g., red used to start a race), these are generally accepted. Accidents The worst accident in racing history is the 1955 Le Mans disaster, where more than 80 people died, including the French driver Pierre Levegh. Racing-car setup In auto racing, the racing setup or car setup is the set of adjustments made to the vehicle to optimize its behaviour (performance, handling,