Which Would You Rather Have: A Seat Belt or an Air Bag?

A number of readers, in light of our recent column on car seats vs. seat belts for kids, have asked my views on seat belts and air bags for adults. So let me ask you a question: if you could only have one or the other, would you go for the seat belt or the air bag.

It turns out the answer is easy, and my views on this one are much less controversial than on car seats. With Jack Porter, a professor at
Wisconsin, I wrote a paper published four years ago that looks at the effectiveness of seat belts and air bags for adults. We found that wearing a seat belt reduced the chance of death by 60-70 percent across all crashes. We estimated that air bags reduce the death rate by 15 percent in frontal crashes, but don’t help in partial frontal, side, or rear crashes. (The benefits we found for adults in seat belts were higher than most previous research, and the results on air bags were lower than in most earlier research. But there is nobody who knows the data who would prefer an airbag to a seat belt if it was an either/or choice.)

The bottom line is that to save a life with a seat belt costs $30,000; to save a life with an air bag costs $1.8 mm by our estimates. This makes seat belts an incredibly effective safety innovation. While in comparison, air bags look bad, indeed in the scheme of things $1.8 mm to save a life is pretty good by regulatory standards.

Along the way in doing this research, we also were able to dispatch with an urban legend. I have heard people say a number of times how drunks manage to survive crashes better than sober people, which has led ER docs to hypothesize that having alcohol in your system relaxes you and allows you to better absorb the blow of the crash. It may surprise you that drunks really are more likely to survive crashes. But the reason isn’t that they are “loose,” it is that the person who makes a mistake in a crash often rams the front of their car into the side of the innocent person’s vehicle. And for survival purposes you would much rather be the one ramming another vehicle than the one getting broadsided.

Speaking of urban legends, anyone know where we can find OrangeJello, LemonJello, and Shithead? Seriously, we want to talk to them.

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  1. My mother-in-law apparently was colleagues with their teacher. Ironically, I was just asking her about it this morning (as I thought it was her, but turns out, it was just someone she was in graduate school with). If I can dig it up, I’ll email it.

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  2. I expect that one thing left out of the statistics is that airbags reduce the number of suicide attempts from running into trees and bridge abutments, especially suicides by people who want their deaths to appear to accidents, for insurance purposes. If your car has an airbag, you can’t very easily kill yourself this way. But I have no idea about the size of this effect.

    Of course you can still do so by pulling out in front of a train or truck (if your car doesn’t have side airbags or curtains), but many people contemplating suicide don’t really want to inflict that on the driver of another vehicle.

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  3. Abbot Uhhm says:

    When I was growing up the stories about the drunks surviving crashes usually involved out-of-control, went off the road, hit a tree accidents. Having survived one of those myself (stone-cold sober) I’d say we tend to attribute a reason to things that sometimes either don’t make any sense, or are just the results of the finger of God.

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  4. Anonymous says:


    Do you also attribute the high casualty rate among people who get blind-sided to the finger of God? Perhaps the middle finger?

    I’ve got no problem chalking up random lives saved and ended up to acts of God. But don’t you think it’s a bit silly to ignore a common sense explanation (that is, having an engine absorbing much of the crash rather than just the side door) combined with the data showing the hypothesis is true?

    I think we have a tendency to attribute God as a reason to things we don’t understand, rather than just admitting that we don’t know.

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  5. Abbot Uhhm says:

    Well no. I think there’s a reasonable assumption that the blindsided are more likely to be injured than the blindsider. I actually saw this illustrated when a Saturn wagon blindsided and knocked over an SUV, disproving the lie that SUV’s greater height makes them safer vehicles. My comments were about drunks involved in single car off-the-road accidents.

    You are correct that I do not know why I survived the rollover down the canyon.

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  6. Anonymous says:

    Your blog is not clear as to what benefit airbags are to individuals wearing seatbelts. Or is that the cost/benefit ratio you cited fir airbags?

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  7. Anonymous says:

    Air bags may be worse than most folks think. maybe UNsafe.

    Our 2005 Honda CR-V was hit broadside by a Ford F250 truck as the truck pulled out of a gas station.
    (Driver probably drunk – it was a hit & run)
    Speed estimate for the truck: 30MPH to maybe 40.
    We were doing about 20-25 due to traffic light.

    Side curtain airbags went off on my side (front passenger).

    6 weeks later may ears are still ringing loudly. The ENT doc tells me there is no treatment.
    My fade with time – maybe not.

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  8. What do you think of claims that airbags are associated with an increased chance of death in accidents?


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