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June 5, 2005 1:36 PM   Subscribe

Do seat belts save lives?

As a driver, I don't doubt that they increase my chances of surviving a car accident. But are others safer because of a driver wearing a seat belt? What about a passenger?

Does the benefit extend past the specific user?
posted by NotMyselfRightNow to Travel & Transportation (34 answers total)
i understand that wearing a seatbelt in the back can help save the person in the front from being injured (impact of the person behind throwing a movable seat forwards, crushing occupant against dashboard or seatbelt) - there was a tv campaign based on this last time i was in the uk.
posted by andrew cooke at 1:42 PM on June 5, 2005

During a collision, unbelted passengers have been known to punch holes in the windshield. This is likely more dangerous to the passengers than remaining seated.
posted by SPrintF at 2:03 PM on June 5, 2005

That ad is available online here under "Julie" (it's pretty nasty).

Also, I imagine if people are able to move around too much, it increases the chances of having an accident in the first place.
posted by cillit bang at 2:10 PM on June 5, 2005

When I drove commercial trucks, some of the fleet were equipped with pneumatic shock-absorbing seats. In concert with the seat's rather non-bucket-like nature, the seat sometimes took on a 007-esque ejection property. In this situation, the difficulty of controlling a 40,000 lb vehicle whilst careening about the admittedly spacious cab became immediately apparent. I am unaware of any research into flying drivers as a cause of accidents, but personal experience drunkenly sliding back and forth in the vinyl back seat of a cab suggests that a belted driver is less likely to lose control of a vehicle in rough conditions.
posted by stet at 2:16 PM on June 5, 2005

Remembering the idea that wearing a seatbelt might allow the driver to maintain control of the vehicle when he otherwise couldn't is what keeps me wearing one when I'm driving.

The usual benefit of requiring people to wear seatbelts that I've seen used to justify the laws is more of an abstract argument. Some variation on everyone paying less for car insurance if fewer people kill themselves in this way. Or something like that.
posted by sfenders at 2:26 PM on June 5, 2005

I'd never seen the "Julie" advert before, and must say it looks dubious. If you slow the video down, it appears that her son's face slams into the headrest of the passenger seat, which causes a sharp? thump that then causes blood to shoot out the front of her head. I don't get how that actually happens.

Would probably have been more realistic to have her neck snap forward, then live the rest of her life as a quadraplegic, but then, no blood & guts and the message is lost, I guess.
posted by Civil_Disobedient at 3:00 PM on June 5, 2005

Does the benefit extend past the specific user?

There is no question that individual drivers benefit from the introduction of setbelts, in terms of reduced injuries and deaths in accidents. But your question asks whether other people benefit. There are several different classes of people who might benefit or be harmed from the use of seat belts by drivers:

1) Friends and family members benefit from the use of seatbelts by drivers, because they will be less likely to have to grieve over the injury or death of a loved one, and less likely to have to bear the financial and emotional burdens of caring for someone seriously injured in an accident.

2) Insurance companies benefit, because there are fewer payouts for severe injuries or deaths. This is why health insurers increasingly pay for preventive medicine. Fewer major injuries and deaths from accidents also means less money spent on emergency services, hospitalization, health care, etc.

3) There is some debate about whether other drivers and passengers benefit from drivers wearing seatbelts. The theory of risk compensation argues that people will adjust their behavior in response to perceived changes in risk. In a sense, we all have a set amount of risk that we are willing to tolerate with respect to a given activity - driving, for example. When safety features such as seatbelts (or antilock brakes or bicycle helmets) are introduced, drivers will perceive themselves as safer and will, somewhat counterintuitively, drive faster and less carefully. If this theory is true (and there is empirical evidence supporting it), then we would expect that wearing seatbelts would lead drivers to drive more unsafely - increasing the risk for others (including passengers). Especially if they are driving big-ass SUVs.

All in all, I think its a net gain, and that the overall gains from seatbelts outweigh the possible losses.
posted by googly at 3:09 PM on June 5, 2005

Having flipped an SUV (story below), I'd say yes, they definitely do. I probably wouldn't have been able to walk away, pull out my cell phone and call work to tell them I wouldn't be making it in that day.

Now the mostly boring story: The ice was so bad that I wouldn't dream of going into work, because it would be stupid. I had a 4 wheel drive Blazer, but 4 wheel doesn't help you stop, as most people don't seem to realize.

Work HQ was almost 60 miles away, and there was little ice there. I worked about 30 miles away, and the roads were cleared there quickly. So work wasn't cancelled, even though everything in my (mountainous, semi-rural area) was.

The main road through town was fine. The main road I had to take to work was fine. All salted, easy to drive on. But they didn't bother with the entrance ramp to the main road. so as I saw cars moving at almost full speed, I sped up to about 35 so I would be able to merge (small merge area).

The ramp curved near the top, and that area was completely covered with ice. So as I hit the curve, I kept going straight, sliding into a large ditch on the side of the road. The truck ended up upside down and sideways, and I crawled out through the broken sunroof.

Low speed, but gravity did the work, not my speed. Without the seat belt, I would have very likely injured my neck. The truck was a complete loss, but the only injury I had was from something in the back hitting me in the head. Still not sure what it was, but it left one hell of a bump.

Incidentally, the air bag never went off. Probably a good thing.
posted by bh at 3:16 PM on June 5, 2005

My parents survived a head-on collision due to the fact that they both were wearing their seat belts. I'd say, yes.
posted by ericb at 3:20 PM on June 5, 2005

Also - it's likely that a seat belt very likely would have saved Princess Diana's life.
posted by ericb at 3:21 PM on June 5, 2005

I've crashed two cars (both Honda Civic Type-Rs a 2002 model and a 2004 model) - both at modest speed (the first <60 on a fast mountain road, and the second about 40 on a very bumpy road). In both cases the car rolled and was an insurance write off.
In both cases, I unfastened my seatbelt and climbed out.
Without the belt I'd have been rattled about in the car like - uh, something that rattles around lots inside something else... and I daresay that I wouldn't be around to talk about it now.

Would I ever go anywhere without a seatbelt on? No chance.
Would I ever drive a Civic Type-R again? No chance!
posted by Chunder at 3:22 PM on June 5, 2005

very likely
posted by ericb at 3:27 PM on June 5, 2005

Incidentally, I have, and people close to me have survived a crash that we probably wouldn't have if not for the seat belts. But that is completely irrelevant to the question.

When safety features such as seatbelts (or antilock brakes or bicycle helmets) are introduced, drivers will perceive themselves as safer and will, somewhat counterintuitively, drive faster and less carefully.

That's obviously going to be true to some extent for any safety feature. But I would think in the case of seatbelts, the effect would be very small indeed. I think people generally underestimate them, which hypothesis would be consistent with all the people feeling the need to argue that yes, they do actually make you safer, whenever this kind of thing is discussed. Seatbelts are so ubiquitous (every car I've been in for like two decades has had them) that I don't think anyone's going to think of them, even subconsciously, as some kind of magic ticket to invulnerability. 4wd is for example much more likely to lead to false perceptions of safety because it's less commonly used, and because unlike a seatbelt it makes a tangible difference to the experience of driving.

wearing a seatbelt in the back can help save the person in the front from being injured

The TV campaign probably uses that situation because it's effective in convincing people riding as passengers to wear seatbelts, which doesn't tell you anything about how often it would actually make a difference. But it couldn't hurt, so it must help at least a little.
posted by sfenders at 3:50 PM on June 5, 2005

1 I'd never seen the "Julie" advert before, and must say it looks dubious.
good god man, it's not a snuff movie.

2 the original question was, if i understood correctly, whether wearing a seatbelt ever saves someone else's life. read the "more inside" bit.

(not both addressed to the same person)
posted by andrew cooke at 3:51 PM on June 5, 2005

Didn't Homer Simpson say "Seatbelts? They kill more people than they save!'

I think people sometimes claim that seatbelts injure people while stopping them from dying outright. But I get the strong impression that they do save lives.
posted by skylar at 3:57 PM on June 5, 2005

I work in surgery. I have seen many patients that would have survived or had lesser injuries if they would have had seat belts. Yes, I have seen patients that were injured from other people not being restrained in the vehicle. Seatbelts definately save lives.
posted by 6:1 at 4:13 PM on June 5, 2005

People without seatbelts become projectiles. They are injured or die when they collide with something else at high speed. If that something else is another person, the laws of physics don't favor one over the other; they'll be equally harmed on average.

Just think: would you want a 150lb chunk of wood sitting loose in your car during an accident?

For a simple example, imagine two people in a bench seat, one buckled, the other not. If the car is hit directly on the side, the unbuckled passenger will fly towards the other, and it won't be good for either.
posted by whatnotever at 4:18 PM on June 5, 2005

Just think: would you want a 150lb chunk of wood sitting loose in your car during an accident?

Which is why I am always a little dumbfounded by those who drive with all sorts of shit stacked up on the back shelf. That loose speaker? In a head-on collision, that sucker is going to decapitate anyone so unfortunate as to be in its path. Stupid, so very, very stupid. but, then, most people are
posted by five fresh fish at 4:30 PM on June 5, 2005

And while we're in an accident thread, a couple more thoughts:

For every doubling in speed, impact forces quadruple. And that's only if you're so fortunate as to hit a stationary object. If you impact a speeding car, the forces quickly become insane.
• Among these 5-12 years old, crash injuries are the leading cause of death.
Most of the deaths are passenger vehicle occupants, and proper restraint use can reduce this problem.
• Sitting in the rear instead of the front reduces fatal injury risk by 36 percent among children 12 and younger.

• In a series of tests at the Highway Safety Research Institute of Michigan, male and female adult volunteers were safely fastened to a seat with lap and shoulder belts.
• Each volunteer held a 17-pound "dummy" which represented the size and weight of a six-month-old baby.
• Each was then subjected to simulated 15 and 30 mile per hour impacts. Not one of the volunteers was able to hold onto the "baby."
Even knowing the precise moment of impact and using all their strength, the baby was ripped from their arms and slammed into the dashboard.
from mech. eng. dept. utah
posted by five fresh fish at 4:35 PM on June 5, 2005

As an engineer who has gotten involved with crash testing, let me just say that the car is designed as a system to minimize the damage to occupants of the car on impact. An important part of the system is the seat belt. By wearing a seet belt, you are controlling the way the energy is transferred between you and the car such that the time needed to transfer the energy is maximized. By spreading out the impact time, you minimize the damage to the person.

By the way: The crash tests I worked on were for this car. The tests resulted in the discovery that with the top down, the rear deck lid would translate forward, likely decapitating any rear-seat occupants. Changes were made to the design to make the deck lid pop up, but I, for one, wouldn't trust it with my life.... and Mitsubishi quietly discontinued production shortly afterward with only a few units built.
posted by Doohickie at 4:56 PM on June 5, 2005

devil's advocate:

are there any compelling reasons NOT to wear a seatbelt?

(i always wear mine, but i'm trying to understand why some people don't think seatbelts are necessary.)
posted by Ziggy Zaga at 5:11 PM on June 5, 2005

Ziggy Zaga: Im surprised you havent heard it. THe most common reason I've heard is "the seatbelt will get stuck and then I will burn to death in the car."

But really, outside of the movies how often do you see car crashes where one; the car catches on fire, and two; you can live through it without a seat belt.
posted by Iax at 5:44 PM on June 5, 2005

Lots of things can set cars on fire, the majority of them nonfatal to the occupants. Anyway, a more plausible crash scenario would be ending up underwater. Seems to me that the most unlikely part is the seatbelt getting "stuck". How often does that happen?
posted by sfenders at 6:03 PM on June 5, 2005

The most common reason I've heard is comfort.
posted by SpecialK at 6:13 PM on June 5, 2005

My god, I don't think I've ever seen an Ask Mefi where so many people choose to answer a different question than the one that was asked.

Hello, bh, ericb, skylar, 6:1, whatnotever, et al. RTFQ:

But are others safer because of a driver wearing a seat belt?

Does the benefit extend past the specific user?

NMRN didn't ask about whether seat belts save the lives of drivers (the question you chose to answer), but about whether they save other peoples' lives.
posted by googly at 6:44 PM on June 5, 2005

>Do seat belts save lives?

The consensus among people who study these things is that they clearly do.

> are others safer because of a driver wearing a seat belt?

If you hit something or go off the road the belt will help you stay right side up and in front of the wheel, which is really where the driver ought to be. It is hard to steer properly if you are busy falling on the passenger or using the wheel just to hang on. It will also help keep you from falling on them during an accident. For comparison, would you like someone, even a small someone, to jump out a first story window and land on you?

>Does the benefit extend past the specific user?

Depends. How many hundred pounds of meat do you want to have falling on you?

Ironically, despite the clear safety benefits, I am opposed to mandatory seatbelt and helmet laws. People who want out of the breeding pool should be allowed to go.
posted by Ken McE at 6:54 PM on June 5, 2005

I have a related question: are airbags of considerable benefit to people who are also wearing their seatbelts or are they more designed as a stopgap maneuver to minimize the damage to people who aren't wearing seatbelts? I've mostly driven older cars without airbags and my introduction to them in the news seems to say they're as lethal to younger children as they are helpful to non-seatbelted drivers, but I rarely read about accidents where airbags deploying had real benefits to someone already wearing seatlbelts. This is clearly just anecdotal, but what's the deal with airbags?
posted by jessamyn at 7:04 PM on June 5, 2005

jessamyn, there's a reason airbags are called a Supplemental Restraint System. Seatbelts are your first line of defense in a crash, airbags the second. The belt also helps position you for the airbag.

Regarding the small children, etc., one reason that happened is that the Feds mandated that airbags be designed to work with unbelted occupants, and thus automakers had to deploy the bags with much greater force. Second-generation bags typically can deploy with reduced force in low-speed crashes, and are likly safer as a result. Real-world experience has made them better.

I was nervous when airbags were introduced, but once one at a minimum saved my face and possibly my life, I came to appreciate them. Having said that, if I was a smaller stature person, I would prefer one of the newer systems.
posted by pmurray63 at 7:25 PM on June 5, 2005

I once lost my shit with a patient (after 48 hours on call) who came into clinic with neck and back pain after a rear end collision. She was driving a restored car, which, because it would have decreased its value to have anything non-original, had no seat belts. I told her it was the stupidest goddamn thing I had ever heard of in my life, and her mom followed me out into the hallway and chewed me a new asshole.

I didn't back down from my original assertion, doubly so for the time and effort wasted in clinic on somethng avoidable. Last time I heard, they were getting them installed.
posted by docpops at 7:38 PM on June 5, 2005

jessamyn: Yes. Best = Seatbelts + Airbags. See my post about the car being "designed as a system to minimize the damage to occupants of the car on impact" above. Auto designers see safety as a total system approach, and will use every tool available to them to decrease risk (there are also a lot of more subtle safety measures you don't even notice).
posted by Doohickie at 8:00 PM on June 5, 2005

This guy thinks he had his life saved by not wearing a belt.

I'm inclined to agree, being that he is alive and is the only one who experienced the accident. That being said, having one incredibly lucky strike doesn't make him smart to never wear a belt again. He should know better than to hope the only accident he'll ever be in again will be identical.
posted by shepd at 11:59 PM on June 5, 2005

There are a lot of people who insist that they would have died if they had been wearing a seatbelt. There are also a lot of people who point to Bill Gates to show that you can drop out of college and still be wildly successful. Both types of people seem to forget that the odds are against either occuring. Just because it does happen doesn't mean that you are likely to have it happen to you. I mean, people win the lotto all the time, but for every one winner there are millions of losers. From a simple risk assessment standpoint, you're better off wearing your seatbelt, staying in college, and saving that dollar instead of buying the Powerball ticket.

When I first heard that a seatbelt law had been passed in my home state, I was amazed. It had never occurred to me that a person would get into a vehicle without using one. It had been the rule in my family for all my life. Fewer people suffer massive injury from low-speed collisions because of safety features like seatbelts.

I heard an anecdote from a state trooper who came to our school during drivers training. He said that in the police accident records they had photos of kids who had turned into projectiles because they had not been properly restrained. He said that many of the officers who had to come to accident scenes featuring small children thrown from vehicles wanted to keep these photos and show them to every parent that was pulled over for not buckling up their children. I understand why politically this is a bad idea, but damn, when I see kids turned around in the car waving to me out of the back window I want to force that irresponsible parent to see the photos.
posted by caution live frogs at 7:00 AM on June 6, 2005

are there any compelling reasons NOT to wear a seatbelt?

I have an uncle who insists that it's better to be thrown clear of the car. I have absolutely no idea how he figures that to be a good thing.

Airbags are still a questionable safety device. They do save many lives, yes. They are also implicated in many, many injuries -- injuries that would not have occured had there been no airbags. And the first few generations of airbags were significantly lethal (and they still are, if you're the wrong size). And, finally, they are significantly driving up costs, both in vehicle cost and insurance cost.

IMO, frontal impact airbags are a wash.

I'd be delighted to see frontal airbags eliminated, replaced by side curtain airbags. I always wear a seatbelt, and it is always adjusted to fit. I have absolutely no worries about colliding with the steering wheel or dashboard. I am concerned for impacts that will put my head through the side window. Seatbelts do nothing to prevent that.
posted by five fresh fish at 9:51 AM on June 6, 2005

Googly--Re-read (or READ) my answer.
posted by 6:1 at 10:33 AM on June 6, 2005

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