side impacts-trying to figure it all out!

[mamamia]

Hi-wondering if I am thinking about these things right.

Initially I did not understand how a child's head might come out of the wings in a side impact. I was thinking the seat rotates towards the impact because of the momentum, but now I am thinking that what happens is the car is traveling forward, gets hits on the side, but the child is still moving forward prior to moving with his/her seat towards the point of impact. Is that right?

If that is correct, I wonder how far forward a child's neck could stretch without resulting in death or severe spinal cord injury, and if any side wings-even those on the Wizard or Body guard would contain a child's head in a side impact. So that leads me to wonder if the side impact protection is more significant with regards to the torso than the head in these new seats. This is turn leads me to wonder what are the fatal injuries sustained in children who are riding in a properly used/installed CR. Are they head, neck, torso injuries? Are the injuries caused from the intruding vehicle hitting the child or the energy of the crash being absorbed by the child and causing something like aortic dissections as opposed to head trauma from debris?

My next thought is side curtain airbags. If I am correct in saying the child moves forward then towards the impact the side curtain airbags should provide reasonable protection for injuries unrelated to the head being extended too far. This gets me back to wondering what fatal injuries occur in properly restrained children involved in side impact crashes.

Sorry for the babbling. I think about this stuff too much.

Thanks!

[CPSDarren]

In a direct side impact, most of the movement of the child will be toward the point of impact. Side wings both help contain the body inside the shell and protect it from intrusion. In the most common "T-bone" type of crash with one car moving relatively slowly and being struck at full speed from the side I would think that the movement of the child would be almost directly toward the point of impact.

There will be some forward component to the crash, as the car will naturally begin to slow down. This will be even more pronounced in an offset side/frontal crash. In those cases, the child will also be thrown forward somewhat like in a frontal crash. As you know, in a frontal crash the child's head is thrown forward violently and can cause spinal cord injuries. This is the main reason we like to keep kids rear-facing as long as possible, since this risk is higher for younger toddlers and babies. The forward component in a side impact is much smaller than in a head-on crash, so the risk of this type of injury should be less.

A combination of wings on the child seat and side curtain airbags that cover the entire surface of the windows should be a large improvement in the safety of occupants in a crash with any component of impact from the side.

As for statistics, I don't know that there are many. This recent IIHS report does have some new information:

http://www.iihs.org/srpdfs/sr3805.pdf

I hope that helps!

[mamamia]

As usual Darren-you are full of awesome information. That is the exact kind of information I like to read. I know that simulated crash testing is often the only thing available to us, and is unlikely to be completely representative of real world crashes. It is nice to be able to see the real world info. My husband and I discuss this stuff often when we go for walks at night. We are both scientists, so data is what we like-lol! I think all this info is swaying me towards waiting a while to make sure there are no "bugs" with the Wizard instead of going for the Marathon now. I am not 100% convinced that the seats will offer statistically significant side impact protection than other convertibles, but the difference in cost is minimal. I wish my 3 year old would hurry up and be 40 lbs so I could put her in a bodyguard-I really like the look of that seat, and I think the price is great!

One ? about that report-On page 5 it states
"The misuse of restraints that led to some of the child
deaths could have resulted from well-known installation problems.
There’s widespread incompatibility between child restraints
and vehicle seats and between restraints and the safety
belts that have been used to attach them (see Status Report,
Jan. 16, 1999; on the web at www.highwaysafety.org). To reduce
incompatibilities, all new restraints and vehicles are required to
have a universal attachment system known as LATCH"

Is there a list of seats/vehicles/seats/seat belts incombatilbilities?

Thanks again-I hope you don't mind all the ?'s!!

[bazanna]

i don't know of any list. i think there would be problems with any government or otherwise trusted entity in keeping such a list because then you'd have manufacturers complaining that they are being wrongly criticized, etc. the only info on compatibility that i know of is the compatibility database here http://www.carseatdata.org/selectseat.asp

[CPSDarren]

At the Lifesavers Conference, the IIHS presented the list of vehicles and child seats, and made tables of which vehicles and carseats tended to have better compatibility than others. This was the basis of their report on LATCH compatibility. I do not know if they published these tables somewhere or not.

Thanks for the kind comments:-) As an engineer with physics background, I try my best to apply scientific method even to child restraint issues:-)

[mamamia]

I am not suprised at all that you are en engineer with some phsics background!

Alex Novitzky Alex Novitzky
I think one really anoying habit by drivers is the way that they let their children sit on the driver's lap or front passanger's lap without any seatbelt to start with. then , even if they do have seatbealt, the belft would actully cut into the child in the case of impact. there should be some legislation about htis.

Alex nOvitzky

Alex Novitzky

[Robert]

Most states do have some sort of a child restraint law that would prohibit this. However its the parents that allow this to happen in violation of the law. If these parents know the physics involved in a crash even at low speed, I would hope they would use child seats.

One of the problems I have found out is parents have no idea what occurres in a crash. Thats why when I talk to expectant parents at a hospital, the first thing they are hit with is crash dynamics. Its an eye opener to them.