The Frontal Cortex

Airbags Make You Less Safe

When cars are stocked with airbags in every possible direction – are there ceiling airbags yet? – drivers become more aggressive:

A Purdue University research team that studied five years of motor vehicle accidents in Washington State concludes antilock brakes and airbags don’t minimize accidents or injuries because those systems may encourage riskier driving.

Fred Mannering, a Purdue professor of civil engineering, led the study. The results, which are bound to be controversial with auto makers and safety experts, say the innovations designed to improve safety also make drivers less vigilant.

Mannering calls this behavior “offset hypotheses.”

He notes that when ABS debuted, insurance companies said accident rates actually increased for vehicles equipped with the systems that prevent wheels from locking up while braking.

His team analyzed accident data from Washington over a 5-year period beginning in 1992.

“Our findings suggest the offset hypothesis is occurring and that it is sufficient to counter the modest technological benefits of airbags and antilock brakes,” Mannering concludes. Using accident data and actual driving records, the researchers calculated the probability of being involved in an accident for drivers of different ages and demographics. Mannering says the research models indicate ABS and airbags do not affect the probability of an accident or suffering an injury.

While this study is interesting – people are clearly willing to engage in more risk within an environment that appears safer – I’d feel better about the conclusions if the researchers controlled for other variables, like horsepower. After all, cars with multiple airbags tend to be more expensive, which means they also have bigger engines. Plus, the timespan of the study coincided with the birth of the SUV craze, when every minivan driver suddenly began buying hulking Suburbans.

And I’m still not sure what we can do to remedy this effect. We can’t lie to drivers about the safety features of their car, or convince them that their Volvo is really a combustible Pinto. I’m sure wearing seatbelts also makes us less risk averse, but it’s not like anybody wants to go without seatbelts. If airbags are effective – and not everybody is convinced that they are – then we’ll just have to deal with a few more bad drivers.

Comments

  1. #1 Tara C. Smith
    October 24, 2006

    There’s also a learning curve with anti-lock brakes, since most drivers were taught to pump the brakes instead of keeping it pushed down. I’m more curious what’s happened in, say, 1999-2004 when ABS and airbags are more common, rather than in 1992-7, when all of this stuff was newer.

  2. #2 Mark
    October 24, 2006

    I have strong suspicions about this. For one thing, virtually every car has ABS and this feature is rarely touted. I’m not sure the presence of ABS really enters the consciousness or unconsciousness of a typical driver in a way that would influence his driving. I also doubt that the presence of airbags (since they all have front airbags) or more airbags does anything similar. I would look for other reasons. Of course, I have not read the study, but how does the research identify a cause for what I assume must be a finding of no statistically significant change in accident rates or severity of injuries?

  3. #3 MadRocketScientist
    October 24, 2006

    At the start of August this year I was struck head-on at highway speeds by a drunk driver. I was doing 60 MPH in my highway lane and not driving erratically, the drunk just crossed the center line in front of me and that was it, no time to react.

    Thanks to the seatbelts and airbags and solid construction of my Subaru Outback wagon, my wife and I escaped with minor cuts and bruises, my sisters in the back seat, who had only seatbelts, suffered a broken leg and broken ribs, and my dog, all the way in tha back, was unharmed. The other driver was killed.

    My new Outback has even more safety features.

    Maybe safety devices make people feel invulnerable and take more risks, but I bet it has more to do with inadequate training and a societal lack of responsibility. Too many people drive recklessly, and when they cause an accident, if no one is killed, the reckless one gets a ticket and an increase in his/her insurance. Maybe they should get slapped with attempted manslaughter and serve some jail time or community service to help drive home the seriousness.

  4. #4 DD
    October 24, 2006

    In the early 90′s, while I was working for an airbag company, which had mostly shifted their explosives manufacturing line from defense contracting to automotive restraint systems, my old motor-cycle-riding college roommate suggested this:

    “If we installed a cheap 6-inch steel spike in the middle of the steering wheel instead of an $800 airbag, drivers would slow way down, act more cautious, and we’d have less accidents.”

  5. #5 bigTom
    October 24, 2006

    Clearly, when people percieve that theie car has better safety features, they feel they are entitled to drive more aggressively. Of course the industry wants to exploit safety features for marketing advantage. If we could make them safer, without telling the public….
    It does look like over a significant length of time death and injury numbers have been remarkably constant, although total driver/passenger miles have gone up. So by the metric of death/injury per mile we are making a small amount of progress overall.

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