The 19th International 500-Mile Sweepstakes Race was held at the Indianapolis Motor Speedway on Saturday, May 30, 1931. Race winner Louis Schneider, who led the final 34 laps, was accompanied by riding mechanic Jigger Johnson.

The start of the race was delayed two hours due to rain. Defending race winner Billy Arnold charged from 18th starting position to lead the race by lap 7. Arnold, who had dominated the 1930 race (led 198 laps), proceeded to lead the next 155 laps, and built up a five-lap lead over second place. His rear axle broke on lap 162. He spun in turn four, was hit by another car, driven by Luther Johnson, and went over the outside wall. One of his errant wheels bounced across Georgetown Road, and struck and killed an 11-year-old boy, Wilbur C. Brink. Arnold suffered a broken pelvis, and his riding mechanic Spider Matlock broke his shoulder.

The race was part of the 1931 AAA Championship Car season.

The deadline for entries to be received was midnight on Friday May 1. A record 72 cars were entered, for 40 starting positions. The track was made available for practice at the beginning of the month, and most entries were expected to arrive mid-month.

By the end of the first full week of practice, track activity had been sparse. Several of the top teams were expected to arrive within the next week. In addition, rain and cold weather kept drivers off the track over the weekend and into Monday.

Four-lap (10 mile) qualifying runs were utilized, with 90 mph set as the required minimum speed. Diesel entries were allowed a special rules exception, given them a guaranteed starting position provided they complete their run at a speed of greater than 80 mph. Riding mechanics were required to accompany the drivers on all cars during qualifying.

The first day of time trials was held Saturday May 23, with the track available for qualifying from 10:00 a.m. to 7:01 p.m. (sundown). The minimum qualifying speed for gasoline powered engines was set at 90 mph. Dave Evans was the first car out to qualify, in the Cummins Diesel Special. Evans completed his run at 96.871 mph, well above the 80 mph minimum speed required for diesel-powered entries.

...
Wikipedia