The best-known variety of single-seater racing, Formula One, involves an annual World Championship for drivers and constructors of around 18 races a year featuring major international car and engine manufacturers, and independent constructors, such as Ferrari, McLaren, Williams, BMW Sauber, Toyota, Honda, Renault, Red Bull Racing - in an ongoing battle of technology and driver skill and talent.
The Sports Car Club of America's SPEED World Challenge Touring Car and GT championships are dominant in North America while the venerable British Touring Car Championship continues in the United Kingdom. America's historic Trans-Am Series is undergoing a period of transition, but is still the longest-running road racing series in the U.S. The National Auto Sport Association also provides a venue for amateurs to compete in home-built factory derived vehicles on various local circuits.
