The most important single traffic safety device, the painting of
lines down the center of roads was devised by Michigan, Wayne
County Road Commissioner Edward Hines in 1911 after he saw the
dotted drippings from a leaking milk wagon and struck on the
concept.
He ordered his road
commission to begin center striping all danger spots, curves and
bridges were first, and the immediate reduction of accidents was
impressive. He then ordered the striping of all roads in Wayne
County. When the rest of the state and the nation saw the
results, they began center lining their roads as well.
Incidentally, he was also responsible for the first mile of
concrete roadway. It was in the City of Detroit, Michigan.