Throughout the years, the race has used a number of different qualifying procedures….with the current four-lap (ten-mile) qualifying distance being first introduced in 1920….and has been used every year since 1939….whereas in 2014, the qualifying procedure was refined….such that the pole position winner and the starting grid would be determined over two days. On the weekend before the race (Saturday and Sunday), all cars are entered into a blind draw for the qualifying order….when on Saturday, all entries can make up to three attempts to qualify….with the top 33 cars at the end of the day being locked into the grid….when the top nine cars will advance to a special “shootout” session to determine the pole position. Making a second (or third) attempt automatically forfeits the previous attempt….then on Sunday, the drivers that qualified 10–33 on Saturday have their original times erased….and go out to make a new run…..which determines the grid lineup for positions 10–33. The drivers who qualified 1–9 on Saturday advance to the “Fast 9”….whose cars also have their original time erased…..as each car makes a new attempt which determines the lineup for positions 1–9….including the highly coveted pole position. For each attempt, cars are allowed two warm-up laps….when at that time, a member of the team is stationed at the north end of the main stretch….where he or she must wave a green flag which signals an attempt….or else the car will be waved off. The attempt can be waved off during any of the four laps by the team, driver or race officials…..as the series will wave off the run if it is obvious the run will not be fast enough to qualify and it is getting late in the day. If an attempt is waved off after the run starts….the attempt counts towards the three-attempt limit and the previous time is still forfeited, unless race officials waved off the attempt because of weather.