In the year 2000, Glasgow, Scotland, installed blue
streetlights in certain parts of the city to make them more aesthetically
pleasing, but, shortly afterward they noticed that crime went down in those
areas.
In 2005, a city in
Japan installed blue lights in high crime areas, and crime in the area
decreased by 9%.
A Tokyo railroad
company installed blue lights at train stations experiencing a high number of
suicides, and virtually overnight suicide attempts went to zero.
The so-called Blue
Light effect is not 100% scientifically proven but there seems to be some minor
correlation between the lights and lower crime rates. One theory is that blue
light are subconsciously associated with police presence or maybe blue lights
have a calming effect since they are also used to treat seasonal depression.