There used to be 14 head-on collisions and two deaths on San Francisco’s Golden Gate Bridge every year. In 2015, the authorities installed a central barrier and traffic deaths fell to zero.
Why not install a median barrier on all roads in America? The answer is it would cost too much. The decision about where to put safety features, says Bjorn Lomborg, the Danish political scientist and high priest of cost-benefit analysis, reveals society’s willingness to pay for an extra life. In America, a human being turns out to be worth $10mn.
Though Lomborg is most famous as “the sceptical environmentalist” whose 1998 book of that title and subsequent ones such as False Alarm outraged climate change activists, his core interest is the seemingly dry but actually riveting field of cost-benefit ratios. His Danish think-tank, the Copenhagen Consensus Center, spends its time crunching numbers and sifting academic papers, looking for the best ways societies can spend their money.