[piptastic]

Kyba and colleagues found that streetlights accounted for just 13 percent of the city’s total light visible after midnight. That number would jump to 18 percent if the city did not dim the lights. This means most of the light is coming from other types of artificial lighting.

https://earthobservatory.nasa.gov/images/148259/experimentin...

[joe_the_user]

As far as I can tell, Tucson's sky protection regulations aren't limited to stopping streetlights. "With major astronomical observatories within close range, city leaders enacted an outdoor lighting ordinance in 2012 that requires fully shielded lighting and sets limits on the total light produced at night, especially in natural areas and areas close to astronomy sites."

Edit: The gp does mention street lights in the second sentence but that doesn't imply that's all that's done. And hey, no, that's not all the Tucson does.

https://www.darksky.org/nights-over-tucson/

[seanmcdirmid]

Yes. External house lighting, especially in higher-than-average-crime Arizona, is probably going to keep the numbers up. Also headlights from cars, though there shouldn't be much of that past midnight.

[labster]

Do external lights prevent or reduce crime? If so, by how much?

[treeman79]

Ever walk around in a bad area at night with few lights?

My experience. Was waking in what I thought was a decent area. As soon as sun dropped sketchy looking character were everywhere. Just standing around doing nothing. I assume selling drugs. When I got back to an area with better lighting they were all gone.

[fennecs]

If you are in a bad area you are in a bad area. Just seems like correlation.

[seanmcdirmid]

Two things:

* You don't want your house to be the juiciest target. Having lights prevent it from standing out as a place where someone could just hide in the shadows.

* Lights make your cameras more effective.

I'm not really living in a bad area (town homes go for around $1 million here), but we are close enough to a large unhoused and/or drug-seeking population that we still get a lot of property crime (mainly smash and grab on street-parked cars, but you see people going around looking into houses as well). So while everyone on my street is fairly wealthy (and can be relied on to let you know if something is wrong), we still have to do our due diligence (lights, motion lighting, cameras).

[labster]

Lots of anecdata here but no actual data. If it’s just something that moves crime around, then it’s just people lowering their personal risk to let others pay the externalities. Or maybe external lights reduce the absolute amount of crime. I don’t know.

[treeman79]

Lots of downtowns are very different depending on time

[TheRealPomax]

Why make it sound like cutting down light pollution by a whopping 15% is somehow not significant. If anything, this article explains that there's an obvious and simple way to reduce light pollution by quite a bit.

It doesn't ever require passing any legislation for heaven's sake, it's just a Thursday afternoon municipal planning decision with roll-out spread over a four year period or something to keep costs trivially manageable.

[piptastic]

Here's why from later down: “Light-pollution activists and governments have been very focused on street lighting, and that makes sense because it’s probably the biggest single source and the government has direct control over it,” Kyba said. “But my worry is that most of the growth in light is coming from other applications. If we want to reduce the environmental impact of outdoor lighting, it’s not good enough to change to LED streetlights and then stop. We need to think critically about all the different types of light sources there are.”

[TheRealPomax]

Right, but that's still a weird way to focus on it. Of course it's not enough, but it's a fantastic easy step in a multi-step solution.

[mynameisvlad]

Who said it's not significant?

They're just saying it might not be significant enough to drastically affect the type of lights used, as GP comment implied.