A pit crew member prepares a used tire for a tread-wear inspection April 9, 2016, at the Texas Motor Speedway, Fort Worth, Texas. A small layer of rubber is removed from the tire with a blowtorch and scraper so that a tread-wear indicator device can more accurately read the amount of rubber lost during the previous laps. Before the race began, U.S. Air Force Gen. David L. Goldfein, United States Air Force vice chief of staff, administered the Oath of Enlistment to a group of men and women in the Air Force Delayed Entry Program. (U.S. Air Force photo by Senior Airman Alexander Guerrero/Released)