Does light make people safer? Maybe. Maybe not.

One of the cool things about LED lighting is that it provides opportunities to bring some of the benefits of big, modern infrastructures to developing countries without having to actually build the big, modern (and expensive) infrastructure.

A couple of years ago, I wrote a story for ArchitecturalSSL magazine about people installing solar-powered LED streetlights in remote villages in southern Mexico. Tying these places into the larger electrical grid would have been extremely difficult. But solar LED streetlights allowed the people who lived in those places to get the night light they wanted.

Now there's similar work happening in refugee camps in Haiti, where many people displaced by the 2010 earthquake still live. The change is undoubtedly useful: LED streetlights don't have to be powered by expensive gasoline generators, they're better on the lungs than fires, and the light level is bright enough to allow people to work and live far more easily. But what about physical safety? Surprisingly, there turns out to be a decent amount of debate over whether or not the extra light actually reduces violence and makes people safer. It's an interesting case study in how "common sense" doesn't always match up with reality and how difficult it is to attribute cause and effect in complicated social environments. From at story Txchnologist:

In recent months, the lights have come on at two camps through the efforts of aid groups, the Haitian government and the particular expertise of the Solar Electric Light Fund, or SELF, a Washington, D.C.-based nonprofit that uses renewable energy to provide light and power in developing countries.

The nexus between public lighting and safety is hotly debated in Western countries.

Some studies show a decline in crime after an area is illuminated while other research has found that crime actually increases after lights are installed, though it may be because crime is more visible. These studies are of little value, however, in places with collapsed infrastructure like Haiti, which plunged into darkness after the magnitude 7.0 earthquake flattened entire neighborhoods and killed untold thousands.

The security improvements were immediate. The lights function at full power from 6 p.m. to 12 a.m. and at 50 percent between 12 a.m. and 6 a.m. Reported acts of violence, including sexual assault, declined from about six per week when the installations began in June to one or zero per week when streetlights came online in August, according to J/P HRO data provided by SELF. While it's possible to attribute this drop to other factors – the population of the camp had declined to 23,000 by September and community-based "protection teams" have increased patrols – residents reported feeling an increased sense of security. Increased usage of the latrines also improved Sanitary conditions "significantly," according to J/P HRO.