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.
However, Harroun is given credit for advancing the commercialization of the rearview mirror.
Harroun's was the only car in the 1911 race not to have a riding mechanic onboard -- he mounted a 3-by-8-inch mirror on the hood instead.
He came up with the idea for the mirror after seeing something similar on a horse-drawn taxi when he was a chauffeur in Chicago.