Racing organizations
North America
The National Hot Rod Association (NHRA) oversees the majority of drag racing events in North America. The next largest organization, Feld Entertainment's International Hot Rod Association (IHRA), is about one-third the size of NHRA. Nearly all drag strips are associated with one sanctioning body or the other. The NHRA is more popular with large, 1/4-mile nationally-recognized tracks (although the two fuel classes have 304.8-metre (1,000 ft) races because of safety issues), while the IHRA is a favorite of smaller 1/8-mile [201.2-metre (660 ft)] local tracks (and offers selected races on their national tour under the 1/8-mile format. One reason for this (among others) is the IHRA is less restrictive in its rules, such as rules on nitrous oxide (legal in Pro Modified) and oversized engines (no 500-cubic-inch (8.2 L) restriction in the IHRA's Pro Stock category) and less expensive to be associated.
Prior to the founding of the NHRA and IHRA, smaller organizations sanctioned drag racing in the early years. The first commercially sanctioned drag race on the East coast was reputed to have been held at Longview Speedway (now Old Dominion Speedway) in Manassas, VA. Old Dominion Speedway is currently sanctioned by the SBRA (Southern Bracket Racing Association)