* The LED light will pay for itself in one year! Denver switched 20500 traffic signals to LEDs which saves them $430,000 annually. This also saved criteria pollutant emission and 1440MTCE in annual emissions savings. 'The LED signals have a payback period of less than four years and the total cost savings of over the lifetime of the fixtures is estimated to be over $6.1 million. [17] "As a result, red LED balls pay for themselves in energy savings in about 2 to 5 years, depending on the electricity rate, and red arrows pay for themselves in an even shorter amount of time (less than 1.5 years)"[18] LOOK at table 2.2 on this site it shows the cost saving for each color of bulb.