A suicide barrier is a barrier on a bridge

Bridge

A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...

 (often a so-called suicide bridge

Suicide bridge

A suicide bridge is a bridge used frequently to die by suicide, most typically by jumping off and into the water below ....

 known for suicide

Suicide

Suicide is the act of intentionally causing one's own death. Suicide is often committed out of despair or attributed to some underlying mental disorder, such as depression, bipolar disorder, schizophrenia, alcoholism, or drug abuse...

 attempts), observation deck

Observation deck

__FORCETOC__ An observation deck, observation platform or viewing platform is an elevated sightseeing platform usually situated upon a tall architectural structure such as a skyscraper or observation tower...

 or other structure designed to prevent people from attempting suicide by deliberately jumping. Most suicide barriers are tall and fence-like but horizontal nets, which preserve views, have been used in Bern, Switzerland and are currently being proposed for the Golden Gate Bridge

Golden Gate Bridge

The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the opening of the San Francisco Bay into the Pacific Ocean. As part of both U.S. Route 101 and California State Route 1, the structure links the city of San Francisco, on the northern tip of the San Francisco Peninsula, to...

.

Comprehensive suicide barriers can be very expensive: A proposed barrier on the Golden Gate Bridge has an estimated cost of $40 to $50 million. Other problems are aesthetic: heavy fences are often unsightly, detracting from the appearance of the bridge and the view from the bridge itself.

While studies have shown that a well designed suicide barrier can stop people from jumping at a particular site, no study has shown suicide barriers will actually lower the overall suicide rate, and the largest study to observe the effects of a barrier, published in the British Medical Journal in 2010, showed that after a barrier went up at the Bloor Street Viaduct, the rate of jumping from other bridges in Toronto increased and there was no decrease in the overall jumping rate.

Additionally, while studies have shown easy access to guns has an effect on a region's suicide rate, two studies that looked at regions with access to "suicide" or "landmark" bridges found that the overall suicide rates in these places were not higher than average, despite higher than average jumping suicide rates.

While some believe suicide barriers will save some lives, even if the number of lives saved cannot be statistically accounted for, others have argued that barriers may actually cost lives, especially when they are put up in high traffic areas, where some suicidal people have been stopped by bystanders in the past.