NASCAR has had some unusual rules over the years. At the start of the 1991 season, the series prohibited tire changes under caution periods and cars were assigned stickers to show which lap they were eligible to pit on.The rule, which was recalled in April that same season, made for some dull racing. However, it was introduced following the tragic death of a pit crew member in the final race of 1990 and made sure that cars in adjacent pit boxes did not pit on the same lap.Here are five other surprising NASCAR rules.#1 The 250-Mile ruleBefore 1972, NASCAR counted victories in the Daytona Duel qualifying races as official wins. However, the series changed its policy after 1971 to only count wins in points-paying races of 250 miles or more. This shift also meant that drivers like Dale Earnhardt, who won 12 Duels, saw their official win total drop from 88 to 76.Eventually, the 250-mile minimum rule for official wins went out the window after road and street courses were added.#2 No webbed gloves ruleLast season, Joey Logano was disqualified from a qualifying session at Atlanta for using a modified glove with webbing between the fingers. At first glance, the modification seems minor but the webbing can affect aerodynamics during qualifying.NASCAR considered the glove an aerodynamic aid, which violated the rule against non-approved modifications and Logano's No. 22 Ford was moved to the back of the grid. He was also handed a $10,000 fine.#3 NASCAR owns all car numbersUnlike several other racing series, NASCAR owns the rights to all car numbers and each team has to apply to use a number and pay for its likeness. The number 3, famously used by Earnhardt, was unofficially retired after his death but was later used by Austin Dillon in 2014 after Richard Childress Racing paid a licensing fee.#4 Cars must have matching paint on both sidesNASCAR's rule book does not allow the left and right sides of a car to have different paint schemes. However, the front and rear can be different.Terry Labonte's team painted his car with different designs on each side for the 2014 Talladega race and NASCAR allowed the scheme for qualifying but Labonte's No. 32 Ford paint scheme had to be changed for the race.#5 The 'Lucky Dog' ruleThe "Lucky Dog" rule allows the first car one lap down to regain a lap during a caution period. The rule, which was first used at Dover in September of 2003, was a byproduct of a new safety rule banning drivers from racing back to the caution flag after a yellow flag was displayed. The term "Lucky Dog" was popularized during the broadcast when commentator Benny Parsons used it to describe a car benefiting from it.The rule was to prevent accidents and allow emergency crews to respond more quickly to incidents but, as some argue, it can unfairly benefit drivers who have not earned their position.