LED technology is being widely adopted for use in sustainable traffic signal management. However, the useful life and luminosity characteristics have not been sufficiently studied to provide a life cycle analysis of the technology from a "green" perspective. LED traffic signals fail when their luminous intensity falls below a pre-specified threshold, posing a danger to traffic. This research details a field study of LED traffic signals in Missouri and develops a replacement schedule based on key findings. Rates of degradation were statistically analyzed using Analysis of Variance (ANOVA). Results of this research will provide a methodology for engineering managers in state departments of transportation and local communities in identifying best practices and replacement standards for LED traffic signal technology.