Install blue LED lighting on platforms as a low-cost calming measure

The proposal

Fit blue-tinted LED lighting at platform ends, on the theory that blue light has a calming psychological effect and may deter impulsive acts. Attractive because it is far cheaper and easier to install than platform screen doors. Pioneered by Japanese rail operators.

Why it might work

Proponents argue blue light reduces arousal and impulsivity at the moment of crisis; because installation is cheap, even a modest true effect could be cost-effective.

Evidence (contested)

Before-and-after studies from Japan (Matsubayashi, Sawada & Ueda) reported large decreases — around 74% (95% CI 48–87%) and up to 84% in one company's data — and a follow-up found no displacement to neighbouring stations. But a 2014 critical reconsideration argued the true effect is far smaller: only ~14% of attempts occur both at a station and at night (the only conditions platform lighting could affect), the estimates rest on a single company's data with very wide confidence intervals, and no causal mechanism is established.

Implementation path

Trivial retrofit at platform ends; can be piloted cheaply alongside other measures.

Trade-offs and limitations

Evidence is weak and disputed; the headline reductions are not secure. Blue lights are cheap and probably harmless, but should be treated as an experimental adjunct, not a substitute for barriers. Note that two separate 2014 papers are often conflated — one finding "no displacement, still effective," the other arguing the effect is minimal.