LED traffic signals have several advantages over traditional incandescent type of traffic signals. LED signals enjoy a lifespan ten times longer, resulting in lower maintenance and replacement costs and they are low wattage — a 135 watt red incandescent traffic light is replaced by a 10 watt LED. These advantages translate into dramatically reduced energy costs. Additionally, an incandescent red traffic light burns out at all at once which can cause serious problems, but the comparable LED consists of a hundred light emitting diodes that burn out one at a time so the red LED traffic light is still very functional until the LED is replaced.
While some cities are having great success, other cities with smaller budgets are waiting for prices of LED signals to decline further. The technology used in green signals is fairly new and is more expensive than red and orange signals. Considering the labor cost of change-outs or retrofits, some city officials are delaying installation until the cost of green LEDs are lower. Lower costs will allow them to do a multiple-lamp (red and green) overhaul or a group re-lamp. Yellow signals use the less expensive technology, but are rarely used because the very short duty-cycle of yellow signals compared to red signals minimizes the effect of energy savings. Intensity requirements for yellow signals are also much higher than for red and green signals, requiring more LED components and thus more expense.