As I was picking up my dotter from day care, I saw this family who was picking up their daughter from the same place. Like most friendly Malaysians, I smiled & said hi. The mother said hi back.
To my horror, their daughter was later held by the mother who was seated at the back & the father in the driver's seat. They were about to reverse the car & i stopped them.
"Hi. Its very dangerous like that" ( With a concerned tone, while pointing at her daughter )
"Its okay. I will hold her if anything happens. ( swiftly winding up her window of their new Honda Civic & speeds away)"
Sounds familiar? I'm sure most of us have seen or even done something like what that mother did before. Could be your family. Or your friends.
It was at that point, my engineering sense kicked into high gear. I know she won't be able to hold that child in an accident. But how can I convey this message across?
So I went home, had dinner, pulled out my calculator, watched youtube videos on collision slow motion & estimated how much force you need to hold your child in an accident, & the answer ain't pretty.
From the video above, I estimate the stopping distance (d) to be about 0.5m based on the length of the crumple zone.
Weight of child (m) of 12kg, or same as my 3 year old dotter, & initial speed (u) of 16.7m/s or 60kmh.
The calculation shows that you need 3346 Newtons, equivalent to the force needed to lift 341kg or about 34 packs of 10kg rice to hold that child in place @ 60kmh.
Now, I'm not sure about that mother, but I don't know many people who can lift 34 packs of 10kg rice. Do you know anybody who can do that? And what if you are going faster than 60kmh?
This is a pro weightlifter lifting 221kg, still much less than 340kg but you get the idea.
In the event of a collision, if you can't hold the child, the child will continue to move at the vehicle's speed before collision until he hits something.
How the child is seated before the accident affects which part of the car's interior the child will impact & the kind of forces involved. I analysed a few cases below.
#1: Unsecured child seated at the middle rear seat.
Take a look at this video.
Do you want to know how much force is involved when the child hits the dashboard at that speed?
If the child is seated at the back, chances are by the time his body reaches the front, the car's crumple zone is already crumpled. So when he hits it, the dashboard/windscreen will be relatively stationary. From the slow mo videos, i estimate that it takes about 5cm of dashboard deformation to stop the child. How much force?
Yes, 3411kg. 3.4 Tons!!! According to Google, a Honda Civic weighs about 1.3 Tons. So the impact is equivalent to the weight of more than 2.5 Honda Civics, on your child. Depending on how the child impacts the dashboard, that force could be on his head & neck. Imagine that for a second.
There have been cases of child being flung out of the car. I shudder to even think of the force if the child hits concrete/pavement. These are much harder with shorter stopping distance. Think milimeters.
#2: Child Seated on the lap of an adult that is not wearing seat belt.
To me, this is one of the worst ways a child can be seated. The child will hit the dashboard first with impact similar to the example above. The adult's body will then hit the child. How much force?
Let say you are relatively lightweight at 60kg.
Videos in slow motion sometimes don't capture how violent the impact is. Here is the same video, at normal speed.
#3: Child seated at the back, behind the front seat
Similar to #1, but the child is stopped by the back of the front seat like the video below.
From the video, say the stopping distance is about 0.2m. The force is still about 850kg, or 85 packs of 10kg rice. Still way too high for a child or anybody especially if he hits it head first.
Do note after the first impact, the crash dummy rebounded, followed by a 2nd impact. Plus are you sure the adult will wear seat belt while sitting at the back? If not, see #2 above.
So please, use a child seat. You will not be able to hold your child in an accident. Highly recommend you look for one that meets either United Nations ECE R44/04, or Isofix if your car can support them. They are not that expensive these days.
A quick check online shows you can get R44/04 seats below RM300 & Isofix seats as low as RM479. Get one now!!
Please share this with your family or friends who still refuse to use a child seat. You may just save a life.
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