Blue streetlights are believed to be useful in preventing suicides and street crime, a finding that is encouraging an increasing number...

TOKYO — Blue streetlights are believed to be useful in preventing suicides and street crime, a finding that is encouraging an increasing number of railway companies to install blue-light-emitting apparatus at stations to prevent people from committing suicide by jumping in front of trains.

Although experts are split over the effectiveness of the blue lights, railway companies that already have installed the lighting say they have played a successful role in preventing suicides.

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.

Blue illumination is used for other purposes than preventing crimes and suicides.

A total of 152 blue lights were introduced along a 1.8-kilometer stretch of the Tomei Expressway near the Tokyo interchange in 2001 to try to prevent accidents.

A spokesman of Central Nippon Expressway Co. said, “(The illumination was introduced) as part of our efforts to encourage people to drive safely by instinctively and emotionally appealing to them to calm down.”

Professor Tsuneo Suzuki at Keio University said: “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.”