Garrett Glasgow sent along this study on the effectiveness of suicide barriers on bridges:
With support from mental health workers, elected officials, the California Highway Patrol, and the local community, Caltrans has announced their intention to install a suicide prevention barrier on the Cold Spring Bridge by 2010 at a cost of $605,000. During the course of the debate a number of people have claimed that such a barrier would not only deter suicides at the Cold Spring Bridge, but actually prevent suicides and thus save lives. This claim is unfounded. A review of the evidence presented in favor of building the barrier and my own research reveals that there is no evidence that installing a suicide prevention barrier on the Cold Spring Bridge would save lives.
As Garrett writes, “there is a distinction between preventing suicides and preventing suicides
at a particular location.”