On Sunday, a charter bus crashed in New Orleans, killing 23 people. The vehicle had no seat belts, which are not required in large buses, including school buses. Why are these vehicles exempted from seat belt laws?
The chief justification is a 1987 study by the National Transportation Safety Board (NTSB), which looked at 43 serious crashes involving school buses without seat belts. Researchers concluded that seat belts would have been no help in most of these accidents. The study reasoned that closely-spaced bus seats essentially function as seat belts, in that they prevent passengers from being thrown around. A 1989 National Academy of Sciences study came to a similar conclusion.
But the 1990s saw a series of injuries and deaths in which passengers were tossed around or ejected from the bus. Last year, the NTSB president called for a "re-examination" of the issue, and a NTSB report is due this summer. On Tuesday, USA Today said the report is "expected" to endorse seat belts, though the article doesn't identify its source. Meanwhile, a number of respected organizations--the national PTA, American Medical Association, American College of Emergency Physicians--have endorsed the idea of requiring belts. And in most European countries, school buses have both lap and shoulder belts.
The biggest objection to requiring seat belts is their cost. It can cost $1,100 to $1,600 per bus to add seat belts at the factory, and even more to retrofit a bus. The anti-seatbelt faction often adds that school buses are quite safe right now, with only an average of 11 passengers dying per year in crashes. Though it's rarely stated outright, the argument is that installing seat belts to save some portion of these 11 lives cannot justify the enormous cost.
What in fact would be the cost? Well, there are 440,000 school buses in America. Conservatively assuming that it costs $1,500 per bus to add seat belts, the total cost of mandating their use would be $660 million. Since the average school bus lasts 12 to 15 years, the program would cost between $44 million and $55 million per year. Assuming that seat belts would save all 11 students who die each year, then the program would cost roughly $4 million to $5 million per life saved. If seat belts save only some of the 11 students, then the cost per life would be even higher.
Is a human life worth this much? Some may find the very question callous. Economists reply that it would be callous for safety regulators to duck this question, since overspending on safety in one area usually means underspending on safety in another. At any rate, federal agencies long ago embraced cost-benefit analysis. For instance, the Transportation Department has decided that a human life is worth $2.7 million, a figure that argues against mandatory seat belts. The statistic is based on an estimate of future earnings. On the other hand, a series of economic studies values human life between $3 million and $7 million. These estimates are derived by estimating the wage premium workers demand to accept high-risk jobs.