American open-wheel car racing
American open-wheel car racing, generally and commonly known as Indy car racing, is a category of professional automobile racing in the United States. As of 2025, the top-level American open-wheel racing championship is sanctioned by IndyCar and is known as the IndyCar Series. Competitive events for professional-level, open-wheel race cars have been conducted under the auspices of various sanctioning bodies, and traces it roots as far back as 1902. A season-long, points-based, National Championship of drivers has been officially recognized in 1905, 1916, and each year since 1920. As such, for many years, this discipline of motorsports was known as Championship car racing. That name has fallen from use, and the term Indy car racing has become the preferred moniker.
The machines, typically referred to as "Indy cars", are a formula of single-seat, open cockpit, open-wheel, purpose-built race cars. They compete on a variety of circuits, including ovals, road courses, street circuits, and combined road courses. The most famous and most important event of the season is the Indianapolis 500, held at the Indianapolis Motor Speedway on Memorial Day weekend in late May. Over the decades, Indy cars have been generally similar to those in Formula One, though there are important differences. Though the IndyCar Series is American-based, international races have occasionally been held, in such places as Canada, Mexico, Brazil, Japan, and Australia, as well as Europe.
This form of racing experienced considerable growth and popularity in the decades after World War II. The "Golden Era" of the front-engined roadsters was followed by a decade of innovation and transition in the 1960s. By the late-1960s and early-1970s, the cars had rapidly evolved to rear-engined, formula-style machines. Speeds climbed on the superspeedways to over, while international participation also increased. The sport saw much success, exposure, and popularity particularly during the 1980s–1990s under the sanctioning of Championship Auto Racing Teams. Organizational disputes in 1979 and 1996 split participants and the fanbase among two separate competing series. The sport was re-unified in 2008, and in late 2019, IndyCar and the Indianapolis Motor Speedway were bought by Roger Penske and Penske Entertainment.
Sanctioning bodies
AAA (1902–1955)
The national championship was sanctioned by the Contest Board of the American Automobile Association. The AAA first sanctioned automobile motorsports events in 1902. At first it used the rules of the Automobile Club of America, but it formed its own rules in 1903. It introduced the first track season championship for racing cars in 1905. Barney Oldfield was the first champion. No official season championship was recognized from 1906 to 1915, however, many races were held. Official records regard 1916 as the next contested championship season. Years later, retroactive titles were named back to 1902. These post factum seasons are considered unofficial and revisionist history by accredited historians.Racing did not cease in the United States during WWI, but the official national championship was suspended. The Indianapolis 500 itself was voluntarily suspended for 1917–1918 due to the war. In 1920, the championship officially resumed, and despite the difficult economic climate that would later follow, ran continuously throughout the Depression. Shortly after the attack on Pearl Harbor, all auto racing was suspended during World War II. From 1942 to 1945 no events were contested, banned by the U.S. government primarily on account of rationing. Racing resumed in full in 1946. The 1946 season is unique, in that it included six Champ Car events, and 71 "Big Car" races, as organizers were initially unsure about the availability of cars and participation.
AAA ceased participation in auto racing at the end of the 1955 season. It cited a series of high-profile fatal accidents, namely Bill Vukovich during the 1955 Indianapolis 500, and the 1955 Le Mans disaster.
Through 1922 and again from 1930 to 1937, it was commonplace for the cars to be two-seaters, as opposed to the aforementioned standard single-seat form. The driver would be accompanied by a riding mechanic.
USAC (1956–1978)
The national championship was taken over by the United States Auto Club, a new sanctioning body formed by the then-owner of the Indianapolis Motor Speedway, Tony Hulman. Championship racing continued to grow in popularity in a stabilized environment for over two decades, with the two traditional disciplines of paved oval tracks and dirt oval tracks. During the 1950s, front-engined "roadsters" became the dominant cars on the paved oval tracks, while "upright" Champ Dirt Cars continued to dominate on dirt tracks. In the 1960s, drivers and team owners with road racing backgrounds, both American and foreign, began creeping into the series and the paved oval track cars evolved from front-engine "roadsters" to rear-engine formula-style racers. Technology, speed, and expense climbed at a rapid rate. The schedule continued to be dominated by oval tracks, but a few road course races were added to assuage the newcomers. Dirt tracks were dropped from the national championship after 1970.Some teams raced and won both in F1 and in the US in the 1960s or 1970s, like Team Lotus, McLaren, Team Penske, All American Racers. In 1970s Europe, the British F1 chassis makers formed the Formula One Constructors' Association to represent the interests of their privately owned teams – usually against race organisers, later against factory-backed teams and FIA/FISA, which led to a FISA–FOCA war with boycotts etc. that was ended by a 1981 Concorde Agreement that made F1 a success story ever since.
During the 1970s, the increasing costs began to drive some of the traditional USAC car owners out of the sport. The dominant teams became Penske, Patrick, Gurney, and McLaren, all run by people with road racing backgrounds. There was a growing dissent between these teams and USAC management. Events outside Indianapolis were suffering from low attendance, and poor promotion. The Indy 500 was televised on a same day tape delayed basis on ABC, however, most of the other races had little or no coverage on television.
Towards the end of the 1970s, the growing dissent prompted several USAC car owners to consider creating a new sanctioning body to conduct the races. Meanwhile, two events had a concomitant effect on the situation. Tony Hulman, president of the Indianapolis Motor Speedway and founder of USAC, died in the fall of 1977. A few months later, eight key USAC officials were killed in a plane crash. By the end of 1978, the owners had broken away and founded Championship Auto Racing Teams to wrest control of North American single seater Championship racing away from USAC.
CART & USAC (1979–1981): First open-wheel "split"
was formed by most of the existing team owners, with some initial assistance from the SCCA. Therefore, there were two national championships run each by USAC and CART. The Indianapolis 500 remained under USAC sanction. The top teams allied to CART, and the CART championship quickly became the more prestigious national championship. USAC ran a "rump" 1979 season, with few big name drivers — the only exception being A. J. Foyt. In 1979, USAC denied several of the entries from the CART teams at the 1979 Indianapolis 500. The controversy saw a court injunction during the month, which allowed the CART-affiliated entrants to participate.In 1980 USAC and CART jointly formed the Championship Racing League to jointly run the national championship, but IMS management disliked the idea. USAC pulled out of the CRL arrangement in July. CART continued with the schedule for the remainder of the season. Both CART and USAC awarded separate national championship titles that year, and Johnny Rutherford happened to win both.
In 1981–1982, the Indianapolis 500 remained sanctioned by USAC. The preeminent national championship was now the one being sanctioned by CART. The Indy 500 field would consist largely of CART teams, as well as numerous independent, "Indy-only" teams. Indianapolis was not included as a points-paying round of the CART national championship. In addition, by that time USAC had designated Indianapolis an "invitational" race, offering entries only to invited teams. That moved in part to prevent the uproar over denied entries which occurred in 1979. One further race in 1981 was run by USAC at Pocono. This race was not supported by many CART teams, and featured a mixed field filled out by converted dirt track cars. USAC soon stopped sanctioning championship races outside the Indianapolis 500.
CART & USAC (1982–1995)
Stability returned and the national championship was now run by CART full-time. The Indianapolis 500 was sanctioned singly by USAC, but points were paid towards the CART season championship. The cars and engines used in the CART races and USAC-sanctioned Indy 500 were the same, with only relatively minor rules differences. The Indy 500 field would consist of the CART regulars, and numerous one-off entries. On occasion, some of the "Indy only" entries also elected to participate in the Michigan 500 and Pocono 500 given the increased stature and exposure of those two events.One of the more noticeable rule differences by USAC was allowing "stock block" engines a higher level of turbocharger boost. While most full-time CART-based teams utilized their V-8 quadcam engines at Indy, some of the smaller and "Indy only" teams elected to run stock block engines at Indy, attracted by the boost rules.
USAC's Gold Crown Championship continued, settling into an unusual June through May schedule calendar. This provided that the Indianapolis 500 would be the final race of the respective season. However, between the 1984–85 season and the 1994–95 season, the USAC Gold Crown Championship only had one points-paying race: the Indianapolis 500. As a result, during that timespan, the winner of the Indy 500 would win that year's USAC Gold Crown Championship by default.