Passenger airbags - why?

[DieselE]

Only because there is more car to be destroyed before the impact gets to the rear seat occupants..

Yes but unless the passenger compartment itself crumples, the rear seats deccelerate at the same rate as the front. If prevention of whiplash is the supposed reason for fitting airbags then you would expect them to be fitted in the rear as well.

I'm with BTB500 on this one. I think whiplash injuries are caused when the body is moving rearwards and the head attempts to pole vault over the seatback.

 

[grober]

speaking from experience unfortunately!

Yes but unless the passenger compartment itself crumples, the rear seats deccelerate at the same rate as the front. If prevention of whiplash is the supposed reason for fitting airbags then you would expect them to be fitted in the rear as well.

I'm with BTB500 on this one. I think whiplash injuries are caused when the body is moving rearwards and the head attempts to pole vault over the seatback.

Sorry I have disagree with what your are saying having suffered long term neck damage from a frontal collision ( without airbag) several years ago. The term whip lash refers to the fact the neck is stretched violently in one direction, reaches the limit of its movement, and then rebounds violently in the opposite direction. This can happen from frontal or rear impact although its true in the past the term has been commonly associated with rear impact. Ironically due to head rest safety improvements rear whiplash is rapidly becoming a thing of the past. On the other hand front whiplash is becoming more apparent in otherwise effectively restrained seat-belted passengers without front airbags.

Rear passenger airbags would also be desirable but might be difficult to engineer effectively, but I bet Volvo,Saab, Mercedes etc are working on it!

 

[BTB 500]

While rear movement can be quite damaging, the same goes for forward movement and banging your head against glass or steel.

If wearing a seatbelt I don't see how a front seat passenger can bang their head into anything solid, certainly in the cars we have?!

As regards forward movement, I can tip my head forward until my chin hits my body without any particular strain or discomfort. Tilting my head backwards by anything more than a relatively small amount is a different matter.

The USAF carried out experiments on extreme deceleration in the 1950s, using a rocket-powered sled that stopped abruptly by slamming into a trough of water . The human volunteer on that didn't have anything to stop his head moving forward:

And he survived repeated runs without any neck injuries AFAIK.

http://www.hq.nasa.gov/pao/History/SP-4201/ch2-4.htm

 

[Howard]

The master of understatement as well apparently ....

Afterward Beeding, recovering from shock and various minor injuries, judged that 83 g represented about the limit of human tolerance for deceleration.



I saw a programme on this on cable a while back , he went blind for a period of time as well !

 

[BTB 500]

Found this sequence of an extreme deceleration test on the rocket sled (which was measured at 632 mph on one run )

 

[grober]

As regards forward movement, I can tip my head forward until my chin hits my body without any particular strain or discomfort. Tilting my head backwards by anything more than a relatively small amount is a different matter.

I think the damage done in frontal collision stems primarily from hyperextension of the neck rather than flexion. There's a good review here but primarily talks in terms of rear collisions. http://www.postgradmed.com/issues/2001/03_01/young.htm

I tried to find a good video example of what I'm talking about and found this on the EURO NCAP SITE http://www.euroncap.com/tests/fiat_panda_2004/198.aspx

Have a look at the video of the frontal collision and see the difference in head movement between the driver( with airbag ) and passenger (without). Both would have similar seatbelts with pretensioners. Best seen in the frontal shots towards the end.

I cant comment on the American test without knowing exactly how the guy was restrained but I would be surprised if he didn't suffer long term chronic skeletal damage from these experiments.

 

[MBManInKen]

If wearing a seatbelt I don't see how a front seat passenger can bang their head into anything solid, certainly in the cars we have?!

Not everybody wears their seat belts, even if in this country it is mandatory. I said also that seatbelts are still the prime safety tool.

<<As regards forward movement, I can tip my head forward until my chin hits my body without any particular strain or discomfort.>>

Apart from possible physical injuries to the neck and back muscles, the brain smashing into the skull is a common cause of trauma in rapid head movement. Can lead to all kinds of nasty effects, including death.

The USAF carried out experiments on extreme deceleration in the 1950s

I'd be very cautious in referring to US medical experiments from the 50s as being proof of innocence. This was the era in which people were happily exposed to large doses of radiation, biological warfare components and nerve gases.

 

[BTB 500]

I'd be very cautious in referring to US medical experiments from the 50s as being proof of innocence. This was the era in which people were happily exposed to large doses of radiation, biological warfare components and nerve gases.

I cant comment on the American test without knowing exactly how the guy was restrained but I would be surprised if he didn't suffer long term chronic skeletal damage from these experiments.

Seatbelt/harness only, you can see his head moving forward in the sequence I posted above. He did approximately 50 forward-facing deceleration runs at up to 45G, and remained in the USAF until normal retirement at the age of 60. He died aged 89.

http://en.wikipedia.org/wiki/John_Stapp

 

[MBManInKen]

He died aged 89.

Which is really no statistical evidence at all about this practice being safe, let alone proof that passenger airbags serve no purpose.

I'm frankly astonished at this discussion about a safety feature. If you're so keen not to have it, why not just have it removed from the car? I will keep mine though.

 

[BTB 500]

I'm frankly astonished at this discussion about a safety feature.

Prompted by the trouble a colleague at work is having this week trying to get the passenger bag deactivated on his Ford C-Max (two dealers telling him it can't be done, and a third quoting £350). Plus a number of similar threads here.

As already commented, in an accident rear seat passengers decelerate at exactly the same rate as front seat passengers. Since they don't have this safety feature (airbags), are the rear seats therefore more dangerous?

 

[glojo]

I saw one of these US documentaries and the one I saw showed the human guinea pig looking like he had gone one round with Mike Tyson, George Foreman and Henry Cooper all in one session. I don't want to exaggarate the injuries, but numerous blood vessel burst in his head, his eyes were all puffed up and swollen. He looked yuk.

What have you got against these innovations?

Regards
John

 

[MBManInKen]

As already commented, in an accident rear seat passengers decelerate at exactly the same rate as front seat passengers. Since they don't have this safety feature (airbags), are the rear seats therefore more dangerous?

Possibly, I have no evidence either way, it's not my line of work to comment on this .

The wacking of the head forward is likely to be a possible cause for trauma in the back, although I guess the risk of banging the head against glass is probably smaller provided they wear the seat belts. In my LWB the chance of banging into the front seats is probable also small .

 

[BTB 500]

I saw one of these US documentaries and the one I saw showed the human guinea pig looking like he had gone one round with Mike Tyson, George Foreman and Henry Cooper all in one session. I don't want to exaggarate the injuries, but numerous blood vessel burst in his head, his eyes were all puffed up and swollen. He looked yuk.

That was decelerating from 600 mph though ...