Blue light, safety at night

Glasgow night scene with blue streetlights - photo Ivana Dankova

GUEST BLOG - A previous blog on LED lighting introduced the concept of blue street lights and emerging research about crime. Ivana Dankova is a designer from Slovakia currently studying for her MSc in Medialogy in Denmark. In 2011 she completed graduate design research in Scotland on Glasgow’s blue light project. Here Ivana offers this blog on her research. A longer version will appear in the upcoming issue of CPTED Perspective, the ICA newsletter.

A new innovation in street lighting has appeared in Glasgow, Scotland. In 1999 blue streetlights were installed in order to improve the overall aesthetics of the area as a part of a city enhancement program. During my design research for a graduate dissertation I investigated whether blue lights have any effect on people and if so, how they affect them.

As with prior research in CPTED, my hypothesis is that the environment in which we live can influence our behavior. It can inspire us to act in certain ways. My Glasgow case study offered the chance to experience the unique atmosphere of a blue-lit street. Some sources mentioned that the crime surprisingly dropped after blue lights were installed. However, since I could not find further statistics on blue lights in Glasgow, I decided to explore it on my own.

Even though crime reduction was not the initial purpose behind the installation, the street appeared to have a much calmer effect than surrounding streets with traditional sodium yellow/orange lighting.

Even at dusk, blue lights add ambience - photo Ivana Dankova

One possible theory explaining this effect is that since short wavelength blue light produces serotonin in the human brain (which is a calming hormone) it is possible this creates a calming impact on pedestrians. My observation is that people react positively to the lighting. The overall atmosphere is unique and feels more peaceful, calm, as if time moved slower.

I also learned following the Glasgow example, similar blue lights were installed in Japanese train stations. The number of suicides at Japanese train stations was high and increasing, but after the blue lights were installed the number dropped noticeably.

This reduction in suicides due to blue lights is spreading to other locations due to its positive results. Blue lights definitely provide a new tactic for designers looking to calm outdoor locations.

Light up the night

Cities like Glasgow use blue LED streetlights for aesthetics
photo Gregor Sands

Who is Nick Holonyak Jr.?

You probably don't even know. But nowadays it is impossible to ignore his invention. In 1963 Holonyak invented the Light Emitting Diode (LED). A few years ago Randy Atlas blogged here on LEDs in CPTED. 

Today LEDs are flooding our street scenes. Those eerie, brilliant and glaring LEDs are showing up everywhere from Manilla to Sydney to Las Vegas.

Oakland California, for example, is replacing 241 sodium street lights for LEDs in high crime locations (chosen by police). Cutting crime with LEDs? Do LEDs cut crime any better than other types of street lights. Or at all? What do we actually know? 

We know LED color rendition is excellent and it tends to spread light more evenly. LEDs can create glare in rainy or snowy conditions. Because LEDs give off very little heat, I am told they tend to ice over in ice storms, something heat-generating sodium lights seldom do. 

I can also personally report you'll burn your retinas if you look directly at them (not one of my Einstein moments).

LED glare on the left compared to sodium lighting- photo Chris Dushek

The brighter-is-better crowd loves LEDs. Power authorities are thrilled due to 60% energy savings. LED companies are drooling at booming sales.

Yet, there is a conundrum. On one hand we promote an evidence-based, scientific approach to crime prevention. On the other we adopt LEDs without specific evidence about the effect of LEDs on crime or perceptions of safety. 

The best existing research does show positive effects in some situations for lighting in general. That refers only to lighting quantity, not quality. There is also research showing the reverse. 

It's okay to adopt energy-saving lights. It's delusional to think they'll automatically cut crime. They might. Or they might make things worse.

Blue street lights cast evening hue over Glasgow - photo Jason Hawkes, Daily Mail