Why not remove the green light from our traffic lights?
A quick search suggests there are around 25,000 sets of traffic lights in the UK, with each set containing multiple lights. One estimate says 420,000 lights in total.
If we were to scrap the green light from all these junctions, we could cut the number of bulbs by 33%. Also, as it is the green light that stays on when idle, the energy saved would potentially be much more than 33%. The red and amber lights would only be illuminated when required.
There is the potential problem that you would have less time to react to a traffic signal if you hadn’t seen the green light, but we could just make the amber display slightly longer to compensate for this.
The energy savings could be massive, and it could also help contribute to darker skies at night, and reduced light pollution.
Maybe I have missed something glaringly obvious with my logic here so hit me up with some comments if you don’t agree.