INDIANAPOLIS -- The 1930s started with America plunging into the Great Depression and ended with the United States about to enter the World War II.
But the '30s were a decade when the Indianapolis 500 continued to gain stature and cemented itself as one of the country's top sporting events -- indeed, a national treasure.
The economic state of the nation was not the reason the Indy 500 adopted the so-called "junkyard formula" in 1930 that sought to lower costs for competitors, but it proved to be a lucky stroke of genius for track owner Eddie Rickenbacker.
Always one of the richest purses in motor racing, the Indianapolis prize fund dipped to $54,450 in 1933 -- down from nearly $94,000 a year earlier and the third lowest total in the history of the race. But the 500 continued to maintain full fields, in part thanks to the low-cost, low-tech formula that allowed normally aspirated engines of up to 366 cubic inch capacity. By the end of the decade, a rear-engine car would make its Indianapolis debut (George Bailey in the 1939 race).
The starting field peaked with 42 cars in 1933, but for safety reasons was reduced to 33 entries lined up in 11 rows of three in
1934 -- a tradition that endures through today. From 1933 to 1938, 10-lap (25 mile) qualifying runs were mandated, to the general displeasure of competitors; four-lap qualifications were brought back in 1939 and have remained a unique Indianapolis tradition ever since.
In fact, many of the great Indianapolis traditions we take for granted now were established in the 1930s.
The most significant year in that regard was 1936; not only was that the first time that the champion was presented with the iconic Borg-Warner Trophy, it was the first instance of the winner drinking milk in Victory Lane.
As the story goes, Louis Meyer, the first three-time winner of the 500, sought refreshment from cold buttermilk on hot days. In 1936, following his third and final win at Indianapolis, Meyer's buttermilk chug was mistaken for regular milk by a dairy industry executive and milk was made part of the Victory Lane ceremonies a year later.
Meyer was also the first winning driver to be gifted with the 500 pace car after the race. The Month of May 1936 also marked the first time that drivers new to Indianapolis were subjected to a challenging "rookie test," a procedure still mandated today.
On the track, the '30s started with the most dominant performance in the history of the race as Billy Arnold led 198 of 200 laps. Arnold wasn't even on the entry list at the start of the month of May, but was fortuitously drafted in to take over the car of Harry Hartz, who was recuperating from injuries. Due to major crashes in his last two Indy starts, Arnold retired after competing at the Speedway only five times (1928 to 1932). Yet his victory from pole position in the 1930 race when he was just 24 is unlikely to be duplicated.
Despite his short career as an Indy car racer, Arnold led three 500s for a total of 410 laps, putting him 12th on the all-time list. His 1930 win was the first for a front-wheel drive car.
The 1937 race was another Indianapolis classic. Wilbur Shaw, who was destined to become one of the most significant figures in the history of Indianapolis Motor Speedway, was the winner in the closest finish in 500 history to that point. The 2.16-second margin of victory would stand as the race record for an amazing 45 years, finally beaten by the thrilling Gordon Johncock/Rick Mears battle in 1982 that was resolved in Johncock's favor by 0.16 second. Shaw repeated as the Indy winner in 1939 and added a third victory a year later.
The '30s spawned several other great drivers. A two-time pole winner and champion of the 1934 race, Bill Cummings was one of the most consistent Indy car drivers of the era. Cummings started from the top 10 on five occasions and finished in the top six four times, including a third-place result in 1935. Fred Frame led laps at Indianapolis in three of his eight starts from 1927 to 1936, including a race-high 58 on the way to his 1932 win.
With top-four finishes in nine consecutive Indianapolis starts, Ted Horn was perhaps the most successful driver to never win the 500. After finishing second at Indy in 1936 in his second attempt, Horn was third or fourth for the next eight years, completing all but one of 1,600 possible laps in that period. Another notable name who never triumphed in the 500, Rex Mays made 12 Indianapolis starts, claiming pole position four times and qualifying on the front row on three other occasions. Mays led nine different races for a total of 266 laps, but his best 500 finish was second place in 1940 and '41.
Finally, Jimmy Snyder made five Indianapolis 500 starts beginning in 1935, but he was killed in an accident at Cahokia, Ill., a month after he claimed pole position and finished second in the 1939 500. Snyder led three of his races at Indy for a total of 181 laps, including the most (92) in the 1938 race. He was also the first driver to run 130 mph at the Speedway and fastest qualifier for the 1937 race.
The '30s was perhaps the most dangerous decade in the history of Indianapolis Motor Speedway. From 1930 to 1934, six drivers, six riding mechanics and an innocent bystander outside the Speedway gates were killed, prompting the sanctioning body of the race (the American Automobile Association) to mandate helmets for 1935.
In 1936, the track's inner wall and a steeply-banked, 10-foot wide "outer lip" that was intended to slow cars before they hit the outer wall (but which often actually served to launch them over it) was eliminated. The Speedway's outside wall was reconfigured to form a 90-degree angle with the 9-degree banking in the turns; the original wall, situated at a 90-degree angle to the ground, remained in place behind the new wall as late as 1992.
In addition, the bricks in several areas on the 2.5-mile track had deteriorated to the point where they were paved over with asphalt. By the end of the decade, only a 600-yard stretch of the main straight remained surfaced in brick.
Although the 500's safety record improved in the second half of the 1930s, the decade ended in tragic fashion when defending Indianapolis champion Floyd Roberts was killed during the 1939 race. Three months later, the man credited as the spiritual founder of the Indianapolis Motor Speedway was dead as well as Carl Fisher, aged 65, passed away in a Miami hospital.
With World War II under way in Europe, the future of the Indianapolis 500 was cast into doubt as the calendar turned to 1940. And while the race would shortly enter a four-year sabbatical due to America's participation in WWII, an exciting new era was looming on the horizon thanks to a most unlikely savior.
John Oreovicz covers open-wheel racing for ESPN.com.