3 Cup Series events in a single season (the season opener, the season's halfway point, and the season finale). The reason why Riverside was the season finale for 1981 was because Ontario Motor Speedway closed after their season ended in 1980. Riverside also hosted drag racing events, between 1961 and 1969, the Hot Rod Magazine Championship Drag Races, "one of the most significant drag racing events" of that era, were held at RIR. The championship offered a US$37,000 prize, greater even than a NHRA national event prize at the time. Carroll Shelby and Skip Barber had racing schools at Riverside to teach students on how to drive around the racetrack and show them the preferred line on how to enter and exit a corner, Barber was the last racing school to be at Riverside when it was closed in 1989. The Four Courses of Riverside The track was built to accommodate several different configurations, depending on the series and race length. The three options on Riverside Raceway were the long course (), the short course (), and the NASCAR () course. The original racetrack had a backstretch from 1957 to 1968. When the track was redesigned in 1969 (it had to close for a water relocation project), turn 9 was reconfigured with a wider radius and banked with a dogleg approach added, to reduce strain on the car's brakes. The fourth track configuration was a drag racing strip. Before any racing event at RIR, track crews added traffic pylons to close off sections of the track. The closed sections were determined by the specific course and cars used during any given race. Throughout its history, various other track configurations were used to adapt the track for events such as off-road, Cal-Club and motorcycle events. Diagram notes: The long course had the backstretch between turns 8 & 9. This version was used primarily for the Los Angeles Times Grand Prix, although the long course was also used for Indy car racing in the mid-1980s. When the 1969 version was built, the dogleg was added so as to ease the transition into Turn 9 (the track had seen numerous brake failure-induced accidents approaching turn 9, and this change was made as a safety measure). In the short course, the track would use turn 7A rather than 8. The "turn 7-7A" configuration effectively shortened the back straight to just over one-half mile in