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Comment by kofejnik | Hacker News Reader

except that child seats are mostly safety theater, of course

Absolutely not the case. A 5 point harness is best. A car seat converts two or three point harness to a 5 point. Which is great, because those soft little bodies need as many touch points as is possible to spread the load of force. We know for a fact that the 5 point harness is the best, that is why race car drivers use 5 point harnesses instead of lap belts.

The three point harness is a good compromise between the uselessness of a lap belt and the incovinience of a 5 point harness. But its certainly not as good as a 5. Point harness.

I think the other reason that street cars don't use five-point harnesses (and why using them is illegal in most states) is that they immobilize your shoulders and neck too well, which makes rollovers more dangerous without a roll cage. You can't lean forward when the roof collapses, so you can be paralyzed.

And it's hard to look towards the rear quarters.

Ah, that's another good point. Turning your head happens a lot more in street driving than racing.

And also they're inconvenient and don't auto adjust.

3-point belts are made to be as quick and fool proof as possible so that people actually use them, and use them correctly. Importantly, they auto-retract so that they are worn in the proper position.

When you put on 5-point belts, you have to 4 times as many latches to operate, and you have to adjust all 5 belts -- and in the proper order. If you tighten the belts in the wrong order, they won't protect you properly. It is not intuitive -- I have a car with 5-points and the passengers who manage to figure out how to latch them almost universally tighten the belts wrong.

Yeah, a 5 point would suck if you had a dress on.

Dumb question: how do race cars and their drivers handle "blind spots"?

Edit to answer my own question: apparently they use spotters that radio in to them whether or not it's clear, and (at least in NASCAR) the cars don't have side mirrors but have an extra long rear view mirror.

They also only drive forwards which helps a lot.

When I was a kid on the farm, all the transmissions in the grain trucks were modified so you could only go forward. Too many accidents driving backwards with bad sight lines. Its a strange thing at first but you get used to always parking with a forward exit.

And less of a modification on an older farm -- backing up horses was hard enough that many older farms will already be designed for one-way traffic, with all eg barns allowing you to pull through.

huh, never thought of that before but that makes complete sense. All the farms I ever worked on were newer mostly created out of irrigation projects from the new deal. All mechanical at that point.

And you're not driving 200 mph.

Lap belts are far from useless; they get you probably 80% of the value of a three point harness. Yes, your torso will flop forward, but particularly for a child's body size there's very little for them to hit.

The heads of very small children are quite heavy relative to the child's size. The concern with a baby is not that they'll hit something, it's that the weight of their head relative to their body will result in spinal injuries.

Consider for instance the $34 million verdict in Texas against Dorel, which failed to warn against placing children under the age of two in forward-facing seats. The kid Cayden was properly restrained in the back seat, but the weight of his head alone was enough to result in spinal injuries that have left him partially paralyzed for life.

We used to laugh at my kid when kid tried to reach for things on the floor and then fell on their head due to the weight of the head relative to the rest of the body -- but that's why rear-facing and five-point is important for children under 2,3 years old.

Oh yeah, a rear-facing infant seat is absolutely a difference-maker - from the talk about "child seats" I thought we were talking about forward-facing seats for children above 3, the benefits of which are pretty marginal AFAIK.

If you've ever tried to buckle a toddler into a standard 3 point belt made for adults, you'll see that the lap belt goes directly across their throat.

Except they're totally not, and saying that is dangerous.

Go look at crash tests of "child car seats" that are nothing more than a box ticking exercise which uses the adult seat, versus a properly engineering seat and you'll see what you are completely wrong.

https://freakonomics.com/2007/01/05/we-are-not-the-only-ones...

That Freakonomics article is from 2007 and was only pointing out that manufacturers don't test all scenarios - not anything resembling your claim that they're just "safety theater". CDC strongly disagrees based on actual accident data (click risk reduction at the following link):

https://www.cdc.gov/motorvehiclesafety/child_passenger_safet....

Wrong. There's about a 70-80% risk reduction for injury: https://pubmed.ncbi.nlm.nih.gov/15094411/

Is there any evidence for that? I know that for example women are more likely to be injured in car crashes because most car seats/interiors are designed around the average man so if be surprised if a human half didn't need to be raised or put in a safer position.

https://www.youtube.com/watch?v=um5gMZcZWm0

https://freakonomics.com/2007/01/05/we-are-not-the-only-ones...

So your "evidence" is a single anecdotal account from over a decade ago?

Actual accident data doesn't back you up...

Don’t men get in more accidents?

Yes, because seatbelts are so effective for us, it turns out there is no selective pressure avoid car crashes.

I didn't know that about seatbelts. All these years of careful driving have been wasted on me.

It only looks that way because we get in more on-purposes.

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