Solid state light with controlled light output

The present invention is generally related to light sources, and more particularly to traffic signal lights including those incorporating both incandescent and solid state light sources. A solid state light apparatus ideally suited for use in traffic control signals provided with optical feedback to achieve a constant light output, preferably by detecting back-scattered light from a diffuser centered above an LED array. The control logic allows for the LEDs to be individually driven, and having their drive characteristics changed over time to ensure a uniform beam of light is generated at an intensity meeting DOT standards, across the life of the device. The optical feedback also establishes the uniform beam intensity level as a function of sensed ambient light to discern day and night operation.