Daytona International Speedway is long and a 500-mile race requires 200 laps to complete. However, the race was considered official after halfway (100 laps/250 miles) had been completed from 1959 to 2016. From 2017 to 2019, the race was considered official after the conclusion of Stage 2 (120 laps/300 miles) when stage-racing was introduced. In 2020, they revised the rule in which a race is considered official at either halfway or the conclusion of Stage 2 (whichever comes first, in this case halfway). The race has been shortened four times due to rain (in 1965, 1966, 2003, and 2009) and once in response to the energy crisis of 1974. Since the adaptation of the green–white–checkered finish rule in 2004, the race has gone past 500 miles on ten occasions (2005, 2006, 2007, 2010, 2011, 2012, 2015, 2018, 2019, and 2020). It took two attempts to finish the race in 2010, 2011, and 2020. The 2020 running is the longest Daytona 500 contested, lasting 209 laps/522.5 miles.