The Indianapolis 500 has served up more than high speeds, countless left turns, razor-thin finishes and spectacular crashes through the years.
The race, scheduled to be run for the 100th time on Sunday before a crowd in excess of 350,000, also has served as an important test bed for advances in vehicle safety and performance.
Technological advancements first tested on the Indianapolis Motor Speedway’s historic 2.5-mile oval have transitioned to everyday production models since the very first race.
Some of those innovations have become more ubiquitous than others, but the race has proved a durable bridge between race car and production car. Here are some key examples.
Ray Harroun, a retired engineer for Marmon, introduced the rearview mirror to a mass audience while winning the first-ever Indianapolis 500 on May 30, 1911, in a Marmon Wasp.
In 1908, Popular Mechanics first detailed how police used a reflector on their vehicle’s dash much like how one would use a rearview mirror.
But Harroun, who retired for good from the Indianapolis-based carmaker after the 1911 race, is given credit for advancing the commercialization of the rearview mirror.
While other cars in the 1911 race featured a second person, a riding mechanic who also doubled as a spotter, Harroun eschewed another body in his Marmon racer for a 3-by-8-inch mirror mounted on the car’s hood. Harroun came up with the idea for the mirror after seeing something similar on a horse-drawn taxi when he was a chauffer in Chicago.
Harroun’s single-seat, six-cylinder car was the only one in the 1911 race to not feature a riding mechanic. However, Harroun still had a co-driver, who drove 35 of the 200 laps.
The next year, riding mechanics were required in all Indy 500 entries, but they were dropped beginning in 1923.
Four-wheel hydraulic brakes
Duesenberg was the first automaker to offer four-wheel hydraulic brakes in a car, according to Lou Phillips’ book Cars. Duesenberg’s innovation came three years before any other U.S. car offered them.
The technology also was found on the racetrack.
The 1921 Indianapolis 500 was the first to have a car with four-wheel hydraulic brakes. The first cars with four-wheel disc brakes appeared on Miller specials in the 1930s. They were developed by noted racing engineer Harry Miller.
In 1922, driver Barney Oldfield ordered a safety harness for his car that was developed by a parachute maker.
Before the 1922 race, there wasn’t much holding a driver back when there was a crash.
Front seat belts became mandatory in the early 1960s in U.S. vehicles. In 2015, seat belt use in the U.S. was 88.5 percent, according to the National Highway Traffic Safety Administration.