Abstract: A system for controlling traffic at a street intersection includes an intersection signal light assembly with a flashing green signal light unit, in addition to the usual red, yellow and green signal light units. A signal controller is provided for the intersection signal light assembly and actuates the flashing green signal light unit during flashing green intervals that precede green intervals in which the green signal light unit of the intersection signal light assembly is actuated. A pre-intersection signal light assembly is located in proximity to a reaction point associated with an approach lane to the intersection. The distance that the reaction point is located from the intersection is determined by considering the reaction time of a driver and the stopping distance of a vehicle in which the vehicle could be safely brought to a stop at the intersection.