Abstract: A method and apparatus to alert motorists of an impending change of a traffic signal includes a traffic signal assembly (10) including individual red, yellow and green signal lights, with control circuitry (2) to sequentially illuminate the green signal light as a constant green for a first portion T1a of time interval T1, followed by a flashing green for a second portion T1b of interval T1, after which the yellow signal illuminates for time T2, the red signal for a time T3, and the cycle repeats. Thus, instead of the green light remaining constantly illuminated during its entire period of timed operation, the modified circuitry causes the green light to flash for the last portion of its operation, thereby indicating to the motorist that the signal is about to change to yellow.