What potential pros and cons can you think of with this energy saving idea?

Here’s the idea: get rid of red traffic lights. So, when the light is green, you go, when the light is yellow, you slow down, and when there’s no light on at all, you stop. I imagine that any one traffic light uses a pretty tiny amount of energy in a day, but changing all of them in the country could probably save significant energy, right?

Do you think this would be more dangerous? My first idea was to get rid of the green light, but my mom pointed out that if no light = go, and the power goes off, crashes will be very likely to occur as people from all directions would think they have a “green light.” I figure if no light = stop and the power goes off, the only thing that will happen is traffic might get pretty backed up because people would probably take a while to realize what’s going on. Which, in turn, uses more energy in the form of gasoline, so there would have to be studies conducted to determine if implementing this is indeed a net gain…

Thoughts? It’s just a totally hypothetical idea, of course.