Ever wonder how the modern LED Traffic Light module works? Well now you know. It's a pretty conventional beefy switch-mode power supply, combined with eight colored LEDs.

The traditional traffic light bulb that sits behind often rather dirty colored glass is 116 watts, while a modern one with a power supply uses 11 watts for the red light, 13 watts for the green light and 22 watts for the yellow light. It's a pretty big savings in electricity, and replacement (the old traffic bulbs had a lifespan a fraction of the modern bulb).