low number of spectators or safety concerns by the drivers, IndyCar will no longer drive super speedways outside of Indianapolis. Michigan Speedway was part of the series from 2002 to 2007, AutoClub Speedway from 2002 to 2005 and a second time from 2012 to 2015, Pocono was used by IndyCar between 2014 and 2019. In NASCAR they are still an essential part of the racing calendar. The closed and partially demolished Texas World Speedway, was the original "sister track" to Michigan. The two-mile oval, with its 22-degree banking, was the site of Mario Andretti's closed-course record of which stood for 12 years. No major professional series have raced at TWS since the 1990s. The 2.5 mile Ontario Motor Speedway was known as the "Indianapolis of the West", but was bought by the Chevron Land Company in 1980 and partitioned for development. Track length disputes NASCAR and IndyCar use different measuring systems to measure the oval race tracks. As a result, the racetracks have lengths of different accuracy. The following table shows the values that NASCAR, IndyCar and CART/CCWS used to determine the lap speeds and track records. By shape A typical oval track consists of two parallel straights, connected by two 180° turns. Although most ovals generally have only two radii curves, they are usually advertised and labeled as four 90° turns. While many oval tracks conform to the traditional symmetrical design, asymmetrical tracks are not uncommon. Classical geometric shapes Additional prominent examples: Tri-ovals The tri-oval is the common shape of the ovals from the construction booms of the 1960s and 1990s. The use of the tri-oval shape for automobile racing was conceived by Bill France, Sr. during the planning for Daytona. The triangular layout allowed fans in the grandstands an angular perspective of the cars coming towards and moving away from their vantage point. Traditional ovals (such as Indianapolis) offered only limited linear views of the course, and required fans to look back and forth much like a tennis match. The tri-oval shape prevents fans from having to "lean" to see oncoming cars, and creates more forward sight lines. The modern tri-ovals were often called as cookie cutters because of their (nearly) identical shape and identical kind of races. Additional prominent examples: Unique shapes There are a lot of oval tracks, which neither have a classical geometric shape nor still represent a modern tri-oval in the strict sense. While