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9.2 Nets at bridges
- Type of measure: Physical and technological /
- Target problem: Suicide / Trespass /
- Effect mechanism: Deter access /
- Evaluation studies: Yes /
Description
What does this measure refer to and what is its objective?
Installing nets, fences or other types of physical barriers at bridges and viaducts to prevent people from climbing on the bridge and jumping or falling from it.
Recommendations
Best practice and lessons learned
- Priority should be given to bridges situated in built-up areas or close to psychiatric hospitals.
- The type of fencing needs to be considered – bars, nets, height, shape, etc.
- Fencing at bridges can be combined with SOS telephones (similar to the Help Lines that are used at stations).
Warning points
Expected difficulties and issues you should pay attention to
- Problem can be that bridge is not the railway property.
- Special consideration may need to be given to bridges that may have architectural protection.
Observations
Other points that you should not forget
- This measure is traditionally dedicated to suicide prevention at bridges. However, a fenced bridge also prevents falling accidents. It may be effective against young people who illegally climb tall structures to practice “skywalking”.
- GRP anti-trespass panels can be fitted to bridge parapets to prevent suicide or to deter people from climbing onto bridge parapets. Such a trial is to be carried out in the UK.
Study results
Data or other evidence supporting the measure's effectiveness
- Suicide rate clearly increased in the period when the barriers were removed, compared to the rate when barriers were in place (Beautrais et al., 2009): Barriers in place (1991-1995): 5 suicides; barriers removed (1997-2002): 19 suicides; barriers reinstalled (2003-2006): 0 suicides. Removal of barriers was followed by a fivefold increase in the number and rate of suicides from the bridge. Since the reinstallation of barriers there have been no suicides from the bridge.
- Hemmer et al. (2017) compared the effectiveness of different suicide prevention measures implemented on bridges and other high structures in Switzerland. The study showed that barriers and safety nets were both effective, with mean suicide reduction of 68.7% (barriers) and 77.1% (safety nets), respectively. Measures that do not secure the whole hotspot and still allow jumps of 15 meters or more were less effective. Further, the analyses revealed that barriers of at least 2.3 m in height and safety-nets fixed significantly below pedestrian level deterred suicidal jumps. Secured bridgeheads and inbound angle barriers seemed to enhance the effectiveness of the measure.
- Okolie et al. (2020) undertook a meta analysis of 14 studies with the aim of evaluating the effectiveness of interventions to restrict the availability of, or access to, means of suicide by jumping. The Authors concluded that the findings from their review suggested that jumping means restriction interventions are capable of reducing the frequency of suicides by jumping. However, due to methodological limitations of included studies, the finding is based on low‐quality evidence. Therefore, further well‐designed high‐quality studies are required to further evaluate the effectiveness of these interventions, as well as other measures at jumping sites.
- Following the interventions, there was an 86% reduction in jumping suicides per year at the sites in question (95% CI 79% to 91%). There was a 44% increase in jumping suicides per year at nearby sites (95% CI 15% to 81%), but the net gain was a 28% reduction in all jumping suicides per year in the study cities (95% CI 13% to 40%). Structural interventions at ’hotspots’ avert suicide at these sites. Some increases in suicide are evident at neighbouring sites, but there is an overall gain in terms of a reduction in all suicides by jumping (Pirkis et al., 2013).
- Survivors of jumps from heights (not on the railway) report that this type of fencing measure might have prevented them from their suicide attempt (NIMH, 2006). Effectiveness and the aesthetics of barriers at bridges have apparently been considered at the University of California in Berkeley (see NIMH, 2006).
- The theory behind restricting access to means (at hotspots) is that it may ‘buy time’ for the individual to reconsider his or her actions, particularly in situations where these actions are associated with impulsivity or ambivalence (Cox et al., 2013).
- If a particular feature of the environment encourages or allows suicide it can be ethical to try to prevent access to that means of suicide, even if there is a risk of substitution (Beautrais, 2007).
last update: 2022-12-01