DD meaning in Business ?

Double Duty also referred to as the Indy-Charlotte Double or Memorial Day Double, is an auto racing term centered around two events held on Memorial Day weekend in most years. The two events are the annual Indianapolis 500, which is the most important Indycar Series race held at the Indianapolis Motor Speedway in Indiana, and the annual Coca-Cola 600, which is a NASCAR Cup Series race held at the Charlotte Motor Speedway in North Carolina. These two events are regarded as significant events for their respective series, as the Indianapolis 500 is the most prestigious race for Indycar while the Coca-Cola 600 has for years been considered one of NASCAR's most important races.

Both races are scheduled to be run on the same day, barring any postponements, with the Indianapolis 500 run in the early afternoon and the Coca-Cola 600 in the evening. For a driver to pull off the “Double”, he/she must compete at Indianapolis first, then board an airplane following the race and fly to Charlotte to complete the feat. By tradition, the Indianapolis 500 champion will not compete in the Coca Cola 600.

The feat was first attempted by John Andretti on May 29, 1994. In 2001, Tony Stewart became the first and only driver to date to successfully complete all 1,100 miles of both races in the same day.

The feat is considered physically demanding and mentally draining as a driver is required to be in a race car for most of the day, cover over one thousand miles in the course of the attempt, and do so with very little rest if any at all. It is similar in concept to the established discipline of endurance racing, but without the help of a relief driver, and the driver withstanding the very different physical demands of an Indycar, which is run with an open cockpit, and a stock car, in which the driver is enclosed.

Four drivers (John Andretti, Robby Gordon x 5, Tony Stewart x 2 and Kurt Busch) have attempted. Of these, Tony Stewart's 2001 effort stands as the best combined result, finishing 6th at Indianapolis and 3rd at Charlotte. The most recent attempt was made by Busch in 2014. He finished in 6th place at the Indianapolis 500, and was the fastest rookie. However, he dropped out of the Coca-Cola 600 with a blown engine mid-race. He completed 906 miles.

Some drivers in the 1960s and 1970s attempted "crossovers," or running both events when they were scheduled on consecutive days, with Donnie Allison competing in both events in the same year.