Blue Streetlight Crime Reduction

Rumor: The installation of blue streetlights in Japan and Scotland caused a reduction in crime and suicide rates.

Claim:   The installation of blue streetlights in Japan and Scotland caused a reduction in crime and suicide rates.


UNPROVEN


Examples:   [Collected via e-mail, May 2015]


I’ve read that blue street lights in Japan and Glasgow are being
credited with drops in crime rates and suicides. I have a hard time
believing that the color of lighting has anything to do with the crime
rate.

 

Origins:   On 21 April 2015 a Reddit thread “today I learned” (TIL) noted “that some areas in Scotland and Japan switched to blue street lights at night and saw a decrease in crime and suicide rates.” The claim referenced in that thread was not a new one and was linked to a 2008 Psych Central article about the belief that blue streetlight installation had reduced crime and suicide rates in Tokyo and Glasgow.

That article claimed “[an] intriguing, anecdotal finding was recently reported by some news outlets that the implementation of blue-colored streetlights has reduced both crime and suicides” but offered a relatively weak case for that finding, quoting a summary of Yomiuri Shimbun article (with details expressed in unprecise terms such as “a few”):



Glasgow, Scotland, introduced blue streetlighting to improve the city’s landscape in 2000. Afterward, the number of crimes in areas illuminated in blue noticeably decreased.

The Nara, Japan, prefectural police set up blue streetlights in the prefecture in 2005, and found that the number of crimes decreased by about 9 percent in blue-illuminated neighborhoods.

Keihin Electric Express Railway Co. changed the color of eight lights on the ends of platforms at Gumyoji Station in Yokohama, Japan, in February.

According to the company, a few people attempt to commit suicide every year at the station.

Since the blue lighting was introduced, no suicide attempts have occurred at the station.


That article made mention of a purported crime decrease in Glasgow, Scotland, following the installation of blue streetlights in certain areas. However, the reason cited for the shift to blue lighting in the Scottish city was aesthetic and not as a deliberate crime prevention tactic, and reliable evidence supporting claims that a switch to blue streetlights affected crime rates in Glasgow remains difficult to pin down.

A November 2009 article from the New York Times was similarly (and suspiciously) vague, quoting Mizuki Takahashi of the Japan Institute of Color Psychology on the potential for suicide prevention presented by blue lighting:



We associate the color with the sky and the sea. It has a calming effect on agitated people, or people obsessed with one particular thing, which in this case is committing suicide.

Notably absent from all these articles was an explanation as to how blue streetlighting was determined to be a suicide or crime deterrent. It’s possible that the cited anecdotal

observations made by police in Glasgow inspired a wider belief blue sreetlights deterred suicide and crime, but no other evidence (anecdotal or otherwise) was referenced in articles about blue streetlights in Glasgow, Tokyo, or elsewhere.

In November 2009, Keio University color psychology professor Tsuneo Suzuki stated that there was “no research that proves that blue lights will dissuade people from killing themselves” and reiterated the opinion he gave railway officials regarding the efficacy of blue lights as a suicide deterrent:



I told them that I understood their concerns but that they won’t solve a deeply rooted societal problem like suicide by putting up lights. If you showed that it was possible, you would probably win the Nobel Prize.

As to the “why” of ostensible crime and suicide dips in areas where blue streetlights were installed, Suzuki surmised that disruption produced by the unusual lighting (and not the color itself) might account for any local changes in behavior:



There are a number of pieces of data to prove blue has a calming effect upon people. However, it’s an unusual color for lighting, so people may just feel like avoiding standing out by committing crimes or suicide under such unusual illumination. It’s a little risky to believe that the color of lighting can prevent anything.

Additional research on blue lights and crime rates was published in 2013 and 2014 in the Journal of Affective Disorders. A May 2013 article titled “Does the installation of blue lights on train platforms prevent suicide? A before-and-after observational study from Japan” stated:



Our regression analysis shows that the introduction of blue lights resulted in a 84% decrease in the number of suicides.

The analysis relies on data from a single railroad company and it does not examine the underlying suicide-mitigation mechanism of blue lights.

As blue lights are easier and less expensive to install than platform screen doors, they can be a cost-effective method for suicide prevention.


A September 2014 article titled “Reconsidering the effects of blue-light installation for prevention of railway suicides” posited that the anticipated effect “should be less than our conservative estimate”:



A recent preliminary communication suggested that the calming effect of blue lights installed at the ends of railway platforms in Japan reduced suicides by 84%. This estimate is potentially misleading from an epidemiological point of view and is reconsidered in the present study.

The installation of blue lights on platforms, even were they to have some effect in preventing railway suicides at night, would have a much smaller impact than previously estimated.


Research published in the same journal in 2014 reported no measurable increase in suicides at neighboring stations, suggesting the installation of blue streetlights did not simply inspire potentially suicidal people to seek out another platform on which to end their lives. For now, the blue light claim falls short in terms of hard and fast evidence: While some limited data suggests a minor effect has been observed areas where blue streetlights have been installed, there is no documentation establishing a definitive causal connection between blue streetlights and reductions in suicide or crime rates.

Last updated:   21 May 2015


Sources:




    Buch, Prateek.   “Network Rail Keen to Improve ‘Blue Light’ Pilot Study.”

    Ask for Evidence.   27 November 2014.

    Grohol, John M.   “Can Blue-Colored Light Prevent Suicide?”

    PsychCentral.   13 December 2008.

    Hall, Kenji.   “Will Blue Lights Reduce Suicides in Japan?”

    BusinessWeek.   5 November 2009.

    “Japan Links Use of Blue Streetlights to Drop in Crime.”

    Chicago Tribune.   19 December 2008.

    “Blue Streetlights Believed to Prevent Suicides.”

    Seattle Times.   11 December 2008.

    “Japanese Railways Hope Soothing Lights Will Curb Suicides.”

    The New York Times.   4 November 2009.


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