Must be a Leotek, They seem to die out in rows, I have replaced many, both ball and arrow. Usually the green ones on the main road and reds on the side as well as red arrows on left turns.
Some of the older ones have died, or have started to flicker. Funny enough only the red and green are affected, unless it is one of the intersections with regular problems. The original Futurit signs that remain are still going strong, even though they were the first installations.