Assembly line production made cars cheap enough for the masses in the early 1900s, but it took a separate set of innovations to convince people to ditch their horse-drawn carriages for internal-combustion vehicles. One important innovation allowed motorists to start their engines without standing outside and turning metal cranks protruding from the fronts of their cars.

Crank starting was not only an inconvenient and laborious task but one that occasionally had nasty consequences. An engine misfire could cause the metal arm to jerk violently, sometimes causing sprains and broken bones. Henry Leland, president of Cadillac, knew firsthand the dangers; a friend of his was struck in the face by a wayward crank and died in the hospital from complications related to a broken jaw. The accident convinced Leland to pursue inventor Charles Kettering's proposal for an electric starter in 1910.