'in force'. Prior to the 1933 race, Howdy Wilcox II (no relation to the 1919 winner) was disqualified when officials found out that he was a diabetic. 1934: Bill Cummings wins by 27 seconds from Mauri Rose, the closest ever finish at the time. 1935: The newly introduced yellow 'caution' light, requiring drivers to slow and hold position, makes its first appearance in race, to eventual race winner Kelly Petillo's advantage as many of the late laps are disrupted by rain, neutralising Petillo's race long battle with Rex Mays and Wilbur Shaw. 1936: Louis Meyer becomes the first driver to win a third time, drink milk (in actuality buttermilk) in Victory Lane, receive the Borg-Warner Trophy, and also receive the pace car as one of his prizes. 1937: Wilbur Shaw leads most of the way but must slow late on to conserve engine oil. Ralph Hepburn catches Shaw in turn 4 on the final lap, but Shaw steps on the gas and pulls away to win by 2.16 seconds – the closest finish at that time. 1938: Floyd Roberts, driving the ill-fated Burd Piston Ring Special, dominates to win by three laps. 1939: Defending winner Floyd Roberts, driving the same car he drove into victory circle in 1938, dies in a crash coming off the second turn onto the backstretch on lap 107. Wilbur Shaw wins his second 500, driving a Maserati. Interesting fact: The Maserati used by Wilbur Shaw was also used by Bill Vukovich to accomplish his rookie test at the Indianapolis Motor Speedway. George Bailey became the first driver to compete with a rear-engined car in the Indianapolis 500 when he contested the 1939 race in a Gulf-Miller. 1940–1949 1940: Wilbur Shaw becomes the second three-time winner and the first to win two in a row in the same Maserati he drove to victory the previous year. The last quarter of the distance is run under the caution flag due to rain. 1941: A fire on race morning destroys part of the garage area and one of the qualified cars. The start is delayed by one hour because of the fire. Wilbur Shaw dominates again, but on lap 152, a wheel collapses, sending Shaw's car into the first turn wall. The wheel is believed to have been one Shaw identified before the race as faulty, and had marked it as not to be used. Water from the