How Does a Bridge Suicide Net Work?

As we noted a few days ago, the Golden Gate Bridge is finally getting a suicide barrier. However, it’s not so much a barrier as it is a net. A steel net, to be specific.

The net will be suspended from either side of the iconic span, and reach out about 20 feet. Out of the five barrier proposals considered, this is the only suicide barrier that will not interfere with tourists’ view from the bridge. It will also allow the 16 painters employed on the bridge to continue their current work routines (the other four barriers would’ve required additional effort and risk for the painters to do their work).

When people jump from the bridge into the net, it will hold them there, suspended some 740 feet over the entrance to the San Francisco Bay.

Denis Mulligan, the chief engineer of the bridge, recently explained to the San Francisco Chronicle how the net works — it envelops the suicide jumper, making it difficult, but not impossible, to get out:

“It wouldn’t be like a trampoline, that once you jump onto, it would be easy to jump off,” Mulligan said. But, he added, “If you’re very agile, very strong and focused, you may be able to climb out.”

The net will be angled and constructed in such a way as to make climbing out of it difficult. The 20 foot drop a person takes into the net will also likely be painful. The paper also described how the process would work in retrieving a person from the net:

During a rescue operation from the net, authorities would shut down a lane of traffic. A specialized vehicle, called a “snooper” truck, would be brought in. Outfitted with a mechanical arm similar to a cherry picker used by utility crews, two specially trained rescue workers would be lowered down to the net in a bucket to pull the person out.

A similar net was installed in Bern, Switzerland. According to the paper, “Researchers found that just the presence of the net stopped people from even trying to jump off the Munster Terrace, a medieval cathedral located in the old section of Bern, from which two or three people had been leaping to their deaths every year. They also found that the net did not shift suicides to other locations.”

Will it work on the Golden Gate Bridge? Prior research suggests that it will at least cut down on the number of successful attempts from the bridge.

After installation of suicide barriers on the Clifton suspension bridge in Bristol, England, researchers there found a significant decline in the number of successful suicides from the bridge. Importantly — and contrary to conventional wisdom — the researchers did not find an increase in jumps from other buildings or bridges in the area. In other words, people didn’t just go find another bridge to jump from.

A net is likely a less effective suicide barrier than a properly designed fence would be. It is hypothesized, however, that the net will work to take away the impulsiveness of the suicidal act. If you know ahead of time that the net is there, and will make it extremely painful and difficult (and in some cases, impossible) to actually complete the act, it’s likely most people will simply not bother trying.

Reference:

Bennewith, O., Nowers, M., & Gunnell, D. (2007). Effect of barriers on the Clifton suspension bridge, England, on local patterns of suicide: Implications for prevention. British Journal of Psychiatry, 190(3), 266-267.

Steel net preferred for halting bridge jumpers, San Francisco Chronicle