To me, it’s acorns and globe post tops. They emit the LEAST amount of light on the road and the most of it goes up and sideways. They look cool, but they’re absolutely horrible street lights. I absolutely despise globe and acorn fixtures without a prismatic lens. The LED COB bulbs they’re often retrofitted with don’t make it better. In fact, they make them worse (even though the HPS, mercury, or metal halide lamps they often had before weren’t much better).

Acorns and globes without a refractive pattern lens are especially bad. There is no cutoff, there are no optics, there is no reflector inside. I don’t like fixtures with clear, white, or frosted round globes or acorns. I’m not sure why those keep being chosen for residential subdivisions. Maybe for decorative purposes. You also shouldn’t shield them.

There are some somewhat cutoff post tops and even some with a horizontal lamp plus a reflector (like the GE TC-100R or the AEL 247), and that made the fixtures function more like a drop lens cobra head. All LED versions of them seem to have the LEDs mounted on top.

Those globe fixtures and acorns cause significant light pollution. So much light is going up into the sky. Acorns and globe fixtures are horrendous. Even worse is that many globe fixtures have the disk thing to hold the globe on, which further reduces light on the road and sidewalk.

Acorns and globes cause so much light pollution, and it’s insane. It makes you not see the stars as well. Acorns and globes without optics shouldn’t even be legal to put on a street.

What is even worse about them, is they’re most common in residential subdivisions which is probably the WORST place for them to be used. These are bad for the environment, they’re bad for people’s health, and all that.

Acorns first were lower wattage E26 incandescent (40-150W), but eventually they made them with high wattage incandescent, HPS, metal halide, or mercury vapor bulbs, which made the issue worse. The new LED ones are just as bad.

I wish all acorns had a refractive or prismatic lens meant to cast most of the light down rather than up into the sky. I get why acorns are used in downtowns and whatnot, but I wish subdivisions just stuck with standard cobra heads. Even a NEMA head would be better than acorns or globes that cast so much of the light into the sky. Thankfully, I never lived in a neighborhood that had acorns.

I can’t imagine how bad light trespass would be in subdivisions that have HPS, MV, MH, or LED acorns.

There are ugly designed cobra heads (like the infamous DuraStar), but at least they emit the light down.

Globe fixtures are even worse than acorns. Their design just makes things worse because it is fully rounded, I’ve seen streets with those horrible fixtures and they’re dimly lighting the roads due to their design. The clear globe ones with the internal refractor was as bad, manufacturers attempted to make them shine more light down, but it didn’t work. Even with the internal refractor, the most of the light was still down and on the sides.