In praise of sodium lighting

Our community center last night at the end of the street

Since 1970 the light source of choice in most cities has been sodium vapor, those yellowish streetlights you see glowing everywhere.

Sodiums are an efficient light source but many lighting engineers despise their color. According to one New York lighting designer "There is this negative subliminal response…the connotation is crime." Says another: "Yellow light muddies the colors of surrounding neighborhoods and makes people feel less secure because the colors around them are not true."

In fact there is very little actual research showing any of that. Most research says nothing about light color, only light quantity.

Regardless, it was only a matter time before a new lighting kid showed up on the block. In this case it was the LED - light emitting diode.

For example Seattle, like most North American cities, is converting to more cost efficient LEDs. They might be more efficient but they they produce a harsh, sharp image on everything.

A decade ago I was guest editor of a publication on lighting and CCTV. My thoughts then: If street lighting enhances architecture where pedestrians can appreciate the facades and details of downtown buildings, there may be problems lighting a downtown so bright it detracts from the aesthetics.

Whenever I see downtown LEDs they remind me I was probably right.

The photos in this blog demonstrate downtown sodium lighting. They show how well-placed sodiums provide adequate lighting and highlight the beautiful textures in downtown architecture.

High risk facilities like automated bank machines can be well lit with sodium

In none of these photos did sodium lighting detract from prevention or turn people off. There are no people in the photos because, at least in the photos I took, I had to wait for them to move aside in order to show the effect. Obviously, sodium lighting did not make them feel less secure. In fact, the opposite.

We know very little about the impact of color on night time behavior, especially crime. And since no one is apparently paying attention to the crime and social impact of LEDs, I hope we don't learn, too late, that brighter isn't always better.

Lighting and crime: Toronto the beautiful

This week I spent time in Toronto, a city with a terrific downtown and dozens of vibrant and healthy neighborhoods. It is also a city with a lighting mish-mash. Bright, glaring halide lights line some streets while yellowish sodium lights line others. There seems no rhyme or reason as far as I can tell.

A decade ago local activists convinced policy folks the bright halide's were the way to go. Their research suggested halide's white color made it easy to see faces at night and reduce pedestrian fear. I’ve never been able to find those studies so I’m unclear how robust they were.

Halides are everywhere on Toronto’s streets. Frankly, in some cases their sharp and glaring impact looks awful. Someone has forgot that, as with all urban designs, one size does not fit all. Some tactics work in one place but not another. Why switch from one lighting form to another without knowing specifically what is actually needed at that place?

The lighting-for-safety debate is decades old. A famous 1981 UK study made the definitive claim that lighting did not decrease crime. Case closed! Or so they thought. Science by definition always challenges assumptions, even well established ones. Lighting studies since then have done precisely that.

In 2004 criminologists Brandon Welsh and David Farrington's in-depth study on CCTV vs lighting concluded: "Improved street lighting is an effective form of surveillance to reduce crime in public space and it has few if any perceived harmful social consequences (unlike CCTV), and may attract less public resistance than CCTV surveillance cameras." Is that the final word? Unlikely. Nor should it be.

Lighting in some places will make places safer. That much is fairly obvious. But when and where? There comes a time when practitioners must act. Smokers may, if they unwisely choose, continue to smoke regardless of the medical research showing it will kill you. Yet we still wisely legislate against media images promoting teenage smoking.

Similarly, perhaps we should start legislating for a proper crime diagnosis in specific places and then installing the proper lighting to fit? We have engineering standards for lighting levels in traffic intersections. We have the Dark Sky folks who want to cut light pollution that drowns out starlight. Why not pressure our local politicians to legislate for a neighborhood by neighborhood diagnosis of proper lighting for safety?

It is not a case of more-light-is-better. Crime is not simple. The lighting-for-safety equation isn't simple. The devil is in the details. Local ordinances and by-laws need to be carefully drafted, not in some generic fashion. But we need to act.