US Patent 7006011 Traffic signal

Systems and methods of controlling traffic including a traffic signal. The traffic signal including one or more lamps configured to each display a plurality of patterns by selectively powering different groups of bulbs. Embodiments of the invention include lamps configured to alternatively display an arrow pattern, a filled circle pattern, a bar pattern or other pattern meaningful to traffic control. The pattern displayed is optionally dependant on available power sources, ambient light, traffic flow, time of day or day of week.