Abstract: A high reliability, low power lamp for use in illuminating traffic signal indicators, comprising a "serpentine grid structure" comprising a first and a second overlapping neon light source. The two neon light sources are placed in close proximity to one another, thus allowing each light source to be illuminated more rapidly due to the reduced length of each tube and the interaction of each tube with the other. The physical layout of the indicator is preferably designed to enhance the operation of the neon tube by causing heat generated by the power supply to raise the temperature of the air surrounding the neon tube.