Description : How did we come to use the colors red, yellow, and green for traffic signal devices at intersections?
Last Answer : http://www33.brinkster.com/iiiii/trfclt/ The world's first three-color, four-direction, elec. traffic lamp, was installed at the intersection of Woodward Ave. and Fort Street, Detroit, Michigan in October, ... , yellow, and green meant stop , caution , and all clear respectively (Brignano 1981).