Current versions of LED streetlamps are absolutely awful. They have very high blue glare which is not only momentarily distracting in peripheral vision and disruptive of sleep cycles but also totally wrecks your night vision. It doesn’t help that they are often turned up to several times brighter than necessary. Same goes for LED car headlamps (especially on SUVs), which should be regulated right off the road. After San Francisco installed some awful LED lamps on my street, I’ve taken to wearing orange safety glasses when I walk my dog, and if I had to drive with any regularity I would consider wearing orange glasses to drive at night.

The excuse I’ve heard that “these are the same color as moonlight” is total nonsense. We don’t have 10 moons hanging 20 feet off the ground on every city block. Nighttime is not supposed to look like daytime. People are not supposed to be reading novels in the street at night, or critically examining the colors of paintings.

Moreover, much of the efficiency story is exaggerated. Recent types of high-pressure sodium lamps are very efficient. The big advantage LEDs have is that they (theoretically) don’t need to be replaced as often. We’ll see how it goes in practice over the coming decades.

The real story of course is that lighting companies have made a big marketing push, and from what I understand there is state/federal grant money available for new LED lighting projects (which are sold as “environmentally friendly”, etc.).

If cities want to use LED street lamps, they should be <3000K correlated color temperature, with as little blue light as possible. They should include diffusers, should be shielded to not shine in the eyes of pedestrians or drivers who aren’t intentionally looking upwards, should be spaced closely enough together that there isn’t a huge contrast between patches of dark and light going down the street, and should be set to a reasonable brightness. Human rod vision is incredibly adaptable to seeing in very dark situations.