Solar streetlights collect solar energy with photovoltaic cells and store the energy in batteries to be used during the night to light the street. During the summer of 2006, units from three different manufacturers were installed on Market Street between 6th and 7th in downtown Louisville. The site was chosen for its solar access to the south, which can be a challenge in city locations. Though the lights could be configured to use conventional electricity as backup. these systems were independent of the grid. Key to the evaluation was performance during December, when day lengths are the shortest, providing the least solar energy to the systems, and when temperatures are cold, which degrades the capacity of the batteries. One system provided light throughout every December night, while the other two had just a few nights (after several days of consecutive cloudy weather) when they ran out of power before sunrise. These tests showed that solar streetlights are a viable option for reducing energy costs and offsetting the environmental impacts of conventional energy production. Solar streetlights can be an economical solution, particularly in remote areas with difficult access to conventional electricity sources.