The world's most famous racing circuit was constructed well before World War I and continues to stand as one of the few tracks that remain largely unchanged since its original construction. Built in 1909, the Indianapolis Motor Speedway has seen a variety of track surfaces, but the rectangular 'oval', built as an automotive proving ground, continues to serve as a measurable bar of reference for innovation and advancement.

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The inaugural Indy 500, held in 1911, was won at an average speed of 74.6 mph and it took Ray Harroun six hours and 42 minutes to complete the 200 laps around the 2.5-mile course. The massive 7.8-liter (477 cu. in.) inline-6 Marmon engine in Harroun's chassis was commonplace during Indy's early years as marine engine technology was heavily utilized.

Qualifying took place for the first time during the 1912 Indy 500, set at 80.93 mph by Gil Anderson, offering a lineal glimpse of how pole position speeds increased to the 226.484 mph average set by Ryan Briscoe in 2012.

Displacements ran as high as 9.6-liters (589 cu. in.) in those early years until a 300 cu. in. limit was imposed in 1915. With advancement in combustion engine technology, aerodynamics and overall vehicle engineering, even halving engine capacity had no effect on speed, as 98.8 mph was achieved in qualifying.

The first major wave of engine technology to hit Indy came at the end of World War I, when supercharging trickled down from fighter planes. Small-displacement European Grand Prix powerplants made an impact, as displacement was reduced to 183 cu. in. for 1920 and to 122 cu. in. for 1923.

Ralph DePalma ran the first qualifying average over 100 mph (100.75 in 1921). By the time the 1.5-liter era hit the track in '23, the smaller, lighter cars helped Tommy Milton move the pole speed to 108.17 mph, the biggest year—to-year increase in the 10 editions of the 500 run on either side of the war.

A drop to 91.5 cu. in. for 1926 would propel Harry Miller to greatness, with his diminutive inline-8s and innovative chassis. In 1927 the entire field used I8s and forced induction—Frank Lockhart also pushed to pole beyond 120 mph, and from there, increased capacity limits and appearances of everything from V16s to rear-engined cars to AWD did little to advance lap speeds at a linear rate.

It took 12 more years for 130 mph to be achieved in 1939 (130.138), until 1954 to average 140 mph (140.033) and finally, by 1962, the then-magical threshold of 150 mph was broken by Parnelli Jones in his front-engined roadster (150.370).

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Jim Clark moved it to 158.828 in 1964 with his rear-engined Lotus featuring Ford's 425 hp four-cam V8, and A.J. Foyt pushed beyond 160 mph for the first time in a Lotus-Ford of his own the following year (161.233).

The sixties marked Indy's wildest decade of innovation, but even turbine-powered cars, twin-engined entries, improved rubber during the Goodyear/Firestone tire wars and the first widespread use of turbocharging could only nudge the speeds just north of 170 mph.

Between 1971 and 1972, proper aerofoils arrived and a certain L-shaped device brought a panic to the Speedway. Al Unser's 1970 pole speed of 170.221 mph was dwarfed by Peter Revson in 1971, when he moved the bar to 178.696 mph. Revson's turbo Offy inline-4 powered McLaren M16 made close to 1000 hp with qualifying boost at his disposal.

Ridiculousness ensued in '72 when Dan Gurney's Offy-powered Eagle, sporting wings with Gurney flaps affixed to the trailing edges, and what could be considered slick tires, allowed Bobby Unser to make Indy's single biggest leap in speed, qualifying at 195.940 mph. The new record represented a staggering 17.2 mph increase in a span of 12 months.

For those who believe aerodynamics have ruined auto racing, blame 1972. Downforce continued to increase in the seventies, and the 200 mph barrier was finally surpassed in 1977 by Tom Sneva (202.156). Engine development stalled until a turbocharged version of Cosworth's DFV F1 powerplant became the engine of choice leading into the eighties.

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F1-derived venturi tunnels saw downforce figures grow, and by 1984, Sneva cracked 210 mph in qualifying (210.029) as Cosworth DFXs, better tires and damper technology came to the fore. 220 mph would fall at the hands of Rick Mears in his Chevy-powered Penske in 1989 (223.885), and Roberto Guerrero, wielding a turbo stock-block V6 grenade from Buick, crossed 230 mph in 1992 (232.842).

Indy's outright track record was set in 1996 by Arie Luyendyk at 237.498—it still stands today—during the final year of turbocharged engines at IMS.

Just as Bobby Unser authored the biggest single-year leap in speeds, Luyendyk has the misfortune to pen the greatest drop in pole speeds when the Indy Racing League went to its brand-new, naturally-aspirated formula for 1997. The sport's collective groan was heard when the Dutchman earned pole with a tepid jog to 218.263 mph, a 19.2 mph free-fall that took the race off the national register.

V8s from 183-244 cu. in ran at Indy through 2011, with a top speed of 231.725 mph by 2003 polesitter Helio Castroneves, but the return to turbos with 134 cu. in V6 single- and twin-turbos from Chevy, Honda and Lotus in 2012 did not hail a new dawn of speed records.

The low-boost mills (18.8 psi) receive an increase for qualifying (20.3 psi), and saw a return to the near-230-mph range, with Ed Carpenter's 228.762 mph speed setting the pole for 2013.

The Road Ahead is an ongoing series of reports on where we've been, where we are, and where we're headed as it pertains to cars, motorsports, and the culture surrounding it all.

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