From The Indianapolis Times, Tuesday, October 31, 1922: This afternoon the traffic signal control system in the tower east of Meridian in Washington St. was tested for its debut tomorrow. Traffic officer George Cox, a ten-year police department veteran, flashed a green light, giving east and west traffic the right of way, an amber light meaning “go” for north south traffic, and a red light compelling all traffic to stop while street cars turned into or out of the traffic. Motorists are to pay no attention to the lights on the tower which serve as signals to traffic officers at intersections who all change their semaphores in unison with the tower lights. Under this system, it is possible for vehicles to go from Alabama St. to Senate Ave. without stopping. This arrangement is expected to facilitate downtown traffic flow considerably.