Editing Drag racing (section)

=== Measurements ===
Several measurements are taken for each race: reaction time, elapsed time, and speed. Reaction time is the period from the green light illuminating to the vehicle leaving the staging beams or breaking the guard beam. Elapsed time is the period from the vehicle leaving the starting line to crossing the finish line. Speed is measured through a [[speed trap]] covering the final {{convert|66|ft|m}} to the finish line, indicating average speed of the vehicle in that distance.

Except where a breakout rule is in place, the winner is the first vehicle to cross the finish line, and therefore the driver with the lowest combined reaction time and elapsed time. Because these times are measured separately, a driver with a slower elapsed time can actually win if that driver's advantage in reaction time exceeds the elapsed time difference. In heads-up racing, this is known as a ''[[holeshot]] win''.<ref>{{cite web|url=http://www.nhra.com/glossary.aspx|title=NHRA Glossary|publisher=NHRA|access-date=11 August 2011|url-status=dead|archive-url=https://web.archive.org/web/20130903044153/http://www.nhra.com/glossary.aspx|archive-date=3 September 2013}}</ref> In categories where a breakout rule is in effect (for example, NHRA Junior Dragster, Super Comp, Super Gas, Super Stock, and Stock classes, as well as some dial-in classes), if a competitor is faster than his or her predetermined time (a "breakout"), that competitor loses. If both competitors are faster than their predetermined times, the competitor who breaks out by less time wins. Regardless, a red light foul is worse than a breakout, except in Junior Dragster where exceeding the absolute limit is a cause for disqualification.