The City of Denver has one of the largest light-emitting diode traffic light inventories in the country.
In the late 1990s, the city's Traffic Operations Division began an ongoing retrofit program to convert its traffic signals from incandescent lamps to LED bulbs. Since then, more than 48,000 red, yellow and green traffic and pedestrian signals have been converted to LED, which saves the city more than $800,000 per year in energy, labor and material costs.