Justification and conceptual design of solar-powered traffic signal systems

Several recent technology developments have established a set of conditions that currently justify the use of solar power for traffic signal systems sited at locations with adequate sunlight. This paper describes those favorable conditions, and how they justify solar-powered traffic signal systems, as they pertain to the state of Georgia, although they also apply more widely to many other states and countries. We also present a review of the state-of-the-art in powering road traffic systems from “green” sources, and a rough analysis of the cost-effectiveness of using solar and/or wind power generators to power traffic signal systems in Georgia. In addition, the results of our investigation into the issue of broadening the batteries' role, when they are required for Uninterruptible Power Supply purposes at critical intersections, are described. Finally, our proposal of a conceptual design of the dual-input power supply architecture required for a “greener” traffic signal system is presented, as are its key specifications. These set the stage for ongoing work to make solar-powered traffic signal systems a ubiquitous reality.