Does the installation of blue lights on train platforms prevent suicide? A before-and-after observational study from Japan

Background: Railway and metro suicides constitute a major problem in many parts of the world. Japan has experienced an increase in the number of suicides by persons diving in front of an oncoming train in the last several years. Some major railway operators in Japan have begun installing blue light-emitting-diode (LED) lamps on railway platforms and at railway crossings as a method of deterring suicides, which is less costly than installing platform screen doors. However, the effectiveness of the blue lights in this regard has not yet been proven. Methods: This study evaluates the effect of blue lights on the number of suicides at 71 train stations by using panel data between 2000 and 2010 from a railway company in a metropolitan area of Japan. We use a regression model and compare the number of suicides before and after and with and without the intervention by the blue light. We used the number of suicides at 11 stations with the intervention as the treatment group and at the other 60 stations without the intervention as the control group. Results: Our regression analysis shows that the introduction of blue lights resulted in a 84% decrease in the number of suicides (CI: 14-97%). Limitation: The analysis relies on data from a single railroad company and it does not examine the underlying suicide-mitigation mechanism of blue lights. Conclusion: As blue lights are easier and less expensive to install than platform screen doors, they can be a cost-effective method for suicide prevention.