A form of automobile racing found mainly in the United States held largely on banked concrete oval tracks of approximately of between approximately 1/2 mile and two miles (about 0.8 to 3.2 kilometres) in length, known as "superspeedways", but also raced occasionally on conventional racing circuits.
Stock cars superficially resemble standard American family sedans, but are in fact purpose-built racing machines built to a strict set of regulations governing the car design ensuring that the chassis, suspension and suchlike are architecturally identical on all vehicles. Engines, whilst containing varying components from the various manufacturers who compete in the series, are of fixed size, and are generally designed to ensure all entrants have near-equal vehicles. There are several categories of stock car racing, each with slightly different rules, but the key intention of cars that look like production cars, but with near-identical specifications underneath, remains true.
The most prominent championship in stock car racing is the NASCAR championship, currently called the Winston Cup after its sponsor. It is very popular. The most famous event in the series is undoubtedly the annual 500-mile race at Daytona.
Fans of other racing series, such as Formula One often have low opinions of the series and its fans, regarding the drivers, cars, and fans as interesting relics of less sophisticated times, with the restrictive regulations removing any possibility for technical innovation. Whilst it is undoubtedly true that stock car racing is less technically sophisticated than many other forms of motorsport, the relative equality of the machinery makes the racing closer and results much more of a test of driver and pit crew ability than more technically-oriented motor racing series that are often decided in wind tunnels and on CAD terminals well before any actual racing takes place. Whilst the challenges of driving and setting up the cars around near-identical banked ovals are probably fewer than learning varied road circuits, the aerodynamic factors giving advantages to a tactically-savvy driver lead to interesting contests which bear some resemblance to some forms of track cycling.