The Washington Post has a great story that illustrates the quandary that regulatory agencies face when they consider new safety measures and that illustrates the use of cost-benefit analysis.
For years, safety advocates have been pressuring the federal government to require seat belts in school buses. The rationale behind this request is as sensible as it is compassionate--seat belts would save lives and reduce injuries among bus passengers.
The National Highway Traffic Administration (NHTSA) has considered the request and rejected it, mostly on cost considerations.
NHTSA found that "that an average of 19 school-age children die in school bus-related traffic crashes each year: 5 are occupants of school buses and 14 are pedestrians near the loading/unloading zone of the school bus." (p. 20). Thus, school buses are already incredibly safe (several times safer than traveling in an automobile), though fatalities still occur.
NHTSA also agreed that seat belts would increase safety and reduce the number of fatalities among passengers. In particular, the agency "estimated that lap/shoulder seat belts would save about 2 lives per year and prevent about 1,900 crash injuries, of which 97 percent are of minor/moderate severity (mainly cuts and bruises), assuming every child wore them correctly on every trip."
So why not require seat belts?
Saving those 2 lives and preventing those 1,900 crash injuries would require enormous costs. NHTSA estimates that seat belts would add $5,500-$7,300 to the cost of each new school bus. Adding up the costs for all new school buses, NHTSA estimates that "the benefits would be achieved at a cost of between $23 and $36 million per equivalent life saved."
Worse, those very high costs could lead to some perverse effects. In particular, the costs would likely lead to school districts using fewer buses and spending less on student and driver training. NHTSA calculates that the likely changes in school district behavior might actually lead to a net loss of 10 to 19 additional lives. Thus, school buses themselves would be safer. However, they would available to fewer children and would be operated in a less safe manner, leading to a greater loss of lives.
NHTSA's analysis not only shows the costs associated with the regulation but how those costs will affect behavior. Regrettably, those high costs will continue to cost some children their lives.