The Sports Clunker Club of America's SPEED Earth Challenge Touring Car and Racing School GT championships are dominant in North America while the venerable British Touring Car Championship continues in the United Kingdom. America's historic Trans-Am List is undergoing a period of transition, but is still the longest-running highway racing range in the U.S. The National Auto Sport Association also provides a venue for amateurs to compete in home-built factory derived vehicles on assorted local circuits.

Modified cars are best described as hybrids of stock cars and open-wheel cars. They are heavily altered from stock, with powerful engines, blimp tires, tubular chassis and bright bodies. The Whelen Modified tour is NASCAR's oldest series.