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Comment by darren | Hacker News Reader

As a parent with 2 young kids the massive size of car seats forced us into a larger vehicle.

Yeah this is a big one. You have to buy specialty car seats now if you want to go three across in a sedan. Admittedly, the seats are much safer (just like the wider cars), but it certainly is a problem.

> just like the wider cars

Safer for the people in the car, not outside it. But I guess that is the point.

From the article in the first paragraph: "To comply with today’s stringent crash regulations – by passing offset, side and roof impact tests, as well as those evaluating pedestrian protection performance – cars require considerable cubic metres of controllably crushable bodywork."

I’m pretty sure the reason an SUV is bigger than a compact has little to do with the differences in the width of the walls.

The article is addressing the size increases in car models between generations. Popularity of SUVs over other types of car is a different issue.

If you mean other people not in cars then picking a lighter car wont matter for the people outside. Airbags on the outside of the car are the only real solution.

0.5mv^2 scales too fast for m1 to matter if m1 >> m2.

It's selfish safety. It is safer for the occupants but it is not safer for the other car in the collision.

Not necessarily. Much of the extra size is to increase the crumple volume. Those crumple volumes absorb energy in a crash, which benefits all involved in the crash. Raw weight on the other hand is an entirely different matter.

Is it physically possible for the energy absorbed by crumple-bits to be greater than the additional energy required to decelerate all the extra mass which the crumple-bits provide?

Yes, the energy required to make permanent deformations in a material is unrelated to it's kinetic energy.

I'd rather get hit in the head by a ten pound blob of clay than a five pound iron ball. (Preferably neither, though.)

I think I'd pick the iron ball? I'd have to feel the clay first.

Would you rather be hit by a moving concrete wall or a moving concrete wall at the same speed but with 5 layers of cardboard boxes taped to it.

"I'm going to buy a car that's safer for pedestrians / other cars in a collision, but less safe for my family" said one person ever.

And that is why we need laws banning these. Someone should care about the non-drivers of cars.

Or will we slowly move to tanks.

Aaaand bring in the Tesla Cybertruck

Some day, there will be a Back To The Future remake, with a Cybertruck.

“You made a time machine... out of a Tesla?”

> And that is why we need laws banning these

You need those laws, because current situation doesn't fit you. I've heard the tank argument for last 20 years over and over. There are tons of use cases when bigger is required, say bigger family, lots of goods being transported etc. I don't have a big car myself, but such statements are pretty ignorant of reality. and what about all the cargo vehicles, trucks etc?

If you want to punish those evil rich capitalists in good ol' communist class envy way, then I have few ideas - we should ban people changing phones in less than 7 years, have only 1 computer per family, every 10 years, only 2 pairs of trousers, no meat for anybody ever, in fact no car and of course only 1 kid max. Its for the greater good, right?

What Switzerland does is, with its car tax is, at least in some cantons, the tax is calculated in equation which considers HP of the car and its weight.

I made this choice. Also not just for pedestrians but for all future people as emissions are lower.

How is maximizing personal gain on the individual level working out? Not well.

I made that choice, too. Crash tests don't give the full picture. Since "downgrading" to a smaller vehicle I've found it much easier to avoid incidents completely. It seems like the right trade off for the kind of driving I do, which is mostly on urban streets.

Ditto. If I crash my bicycle into any car, I'm guaranteed to be the worst off. And a pedestrian would likely be far better off than if I was in a car. (Ps peds get off your bloody phones when crossing the road, especially when emerging from behind a SUV).

This reminds me of one of my favorite philosophy papers:

Vehicles and Crashes: Why is this Moral Issue Overlooked? by Douglas Husak

https://www.jstor.org/stable/23562447?seq=1

Rough summary: there is a high crash incompatibility between SUVs and other cars, imposing unreasonable levels of risks upon the smaller cars.

Simple example (not form the paper): a tank crashes into a car: everyone in the car dies. Had the tank been a regular car, no one would die.

Wider cars are often taller which isn't so safe for pedestrians or bicyclists.

"If you want to fit three across" Why is this limited to child seats? Not like Americans are getting thinner...

It’s not. But 3 across is obviously important because your vehicle selection goes down significantly once you need to expand to a third row to grow your capacity.

I can say from experience that vehicle selection goes down much more once you need to expand to a fifth row. There were just two choices, one from Ford and one from GM.

Fitting three car seats across is still difficult, despite enough car width to have a 4-wide bench in the rear. Putting car seats in the back rows makes them hard to get to, so they should go in the second row or in the third row seat nearest the door. That gives reasonably easy room for 3, but some states would have had me needing 5.

Fifth row? That sounds closer to a bus than a car.

Not sure if serious.

The title/registration stuff does in fact say "bus", but I wouldn't call it that. It's just an extended body van. I get mildly accusatory questions when registering it for non-commercial use and when I go places that have per car or per family payment.

I got the E350. It holds 15 people including the driver, which leaves me just one empty seat when I drive my whole family. Seating is 2-3-3-3-4 from front to back, with an aisle along the right side.

Mine looks just like this one: https://en.wikipedia.org/wiki/File:Ford_E-Series_wagon.jpg

In Europe you would in fact have to have a bus driving license (D or D1) for that kind of vehicle since it can transport more than 8+1 [passengers+driver] (and it most likely also goes beyond the maximum authorized mass of 3500 kg for the B license).

https://en.wikipedia.org/wiki/European_driving_licence#Categ...

You have a 14 person family? Good lord my man.

Fun fact, my mom was the 15th child of 16. My only sister and I worked it out, our grandma was basically pregnant 12 years of her life if it would have been back to back and exactly 9 months each child.

So far nobody has been able to beat my late grandma for children count. Also soup, she made the best soup around.

Just thought I’d throw that one out there. They were spaced out a fair amount though so not like she needed to bus all 16 around at the same time. By the time 16 was not in the oven the first few were already out of the house.

I meant that's cool, but I'd argue that's the nichest of niche uses I've ever seen. And as someone else already said, in Europe you would actually need a full D class licence to drive this in the first place, so you might as well get something like a modified Mercedes Sprinter with 12-15 seats.

I will add that these things do wicked powerslides on gravel roads. It's awesome, especially when all the seats are full.

Sounds like somebody should have used some condoms a long time ago....

Personal attacks will get you banned here. Please don't post like this to HN.

https://news.ycombinator.com/newsguidelines.html

A few years back we got (with a bit of squeezing) three broad-shouldered adults into the back of a friend's Skoda Fabia hatchback [0]. Bit uncomfortable but we fit.

[0]: https://en.wikipedia.org/wiki/%C5%A0koda_Fabia#Second_genera...

You're not wrong, but it's a non sequitur.

Where are you? In the UK you can easily fit 2 kids seats into something like a VW Polo or mini

No way we could get 2 seats in our small 1-Series. While it's fine for my wife when in the passenger seat with the child seat behind her, the drivers seat would be far to forward if we were try to and fit one behind me.

If you're talking about the BMW 1-Series this has a peculiarity that most small cars don't have: a rear wheel drive (or all-wheel in some models) and a longitudinal mounted engine. This means substantially less space inside, especially in the back with the higher floor and the drive shaft down the middle. I found the Polo a lot more spacious than that.

Still I can fit a couple car seats in the back of my E46 wagon.

I second that! VW Polo and two kids work - despite being able to buy about any car there is, we stuck with a Polo until last year. All our gear was bought to fit in it. It is possible to find small stuff that fits. People who say stuff for two kids does not fit in a small car have not thought about it long enough or should seriously consider what their "needs" are.

Buy smaller strollers that are easily foldable, instead of bulky ones. Buy smaller and softer bags so they can fill every gap. Buy car seats that are a bit less space taking. The only time we were in a bit of trouble with space was when we went on a big vacation with 4 people. But that happened only once (admittedly, we usually takes flights when going on vacation).

You can fit two car seats in the back of mine as well -- but only if the parents are both under 5'6" tall and happy to have the front seats as far forward as they go.

My car isn't one of these modern, ever-growing ones, but it's not particularly small in most respects either.

American car seats are huge. A friend of mine, who is not small – even by American standards, despises SUVs and ended up having to import a car seat from Japan for his spawn.

I’ve been wanting to buy a European car seat but am worried about the legality of it. I can just imagine my insurance company refusing to pay for injuries because the seat doesn’t have the right stamp on it.

The Evenflo Tribute LX is a very reasonably priced car seat (~$60), that has very high safety ratings, is parent friendly, and doesn't take up too much space. I regretted buying a much more expensive Nuna after we bought an Evenflo for travel.

I just installed my first iSize isofix car seat in what is a very normal sized Toyota hybrid hatchback that had served us well for years before having children.

I had zero inkling how much space these things take up. With a very ordinary baby seat (not obviously bigger than any of the other 10-20 ones they had at the store) we had to move the front passenger seat so far forwards that it is basically impossible for anyone "tall" to fit in any more.

I am now relectantly planning to buy a larger or SUV car simply because we can't fit anyone in the pasenger seat when we have the baby seat installed. Thought about putting it in the front passenger seat, but it would probably obscure vision.

Excellent! They are generally safer.

Newton's 2nd law:

F1 = -F2

m1a1 = -m2a2 (1)

The longer distance that big vehicles have between people and hard surfaces is a good thing; modern airbags are amazing.

1) glossing over details, because of the way materials scale, this works out (for a smaller human a) even with larger m's on both sides, because there are longer distances involved, and therefore longer crush zones, and more room between humans and hard surfeces for airbags to fill. In accidents that involve a vehicle and a immovable object, this also works out better.

Small vehicles are inherently unsafe, and should come with a disclamer tutorial on basic dynamics.

> Small vehicles are inherently unsafe, and are primarly marketed to people who dont know basic dynamics.

Or to people who need to park their car in a city. Or who rarely have to drive over 50 km/h. Or who can't afford a larger car.

There really are a lot of reasons for having a smaller car, it's quite ingenuous to chalk it up to "not knowing basic dynamics".

Staying alive is more important. Larger cars are not significantly more expensive; people get to choose, some ride motorcycles, it's their choice, but we shouldnt gloss over the 2nd law. Unfortunatly F=ma is not common knowledge. Pointing that out shouldn't be offensive. When one learns that simple rule, they apply it. You quoted when I was still editing, first versions are always worse:)

I think the more relevant equation is a=𝚫v²/(2d) which gives you the acceleration needed to realize a speed change 𝚫v over a distance d. Larger cars allow for a larger d, therefore a smaller peak acceleration in crashes.

edit: I just realized you were focusing on mass. While a higher mass is safer for you, it comes at the cost of making things less safe for everyone else. Making cars larger while keeping mass the same doesn't come with this trade-off, it reduces peak acceleration for everyone.

To your edit: yes, that's what "The longer distance that big vehicles have between people and hard surfaces is a good thing" means.

Larger (modern) vehicles do weigh more; car density does not change much, I would be interested if there is a counter example to that.

Yes, max(a) is the thing to minimize, but to explain it I think starting with the F=ma symmetry is more intuitive, and then point out why d matters.

Why are carseats so big? It can't all be safety. Do you think it gives a luxurious appearance and parents tend to buy them more?

Most prams I see these days are much larger than the simple, light-weight folding models many people had when I was a child in the 80s. They're basically monster-truck-prams.

I think the perceived comfort, safety, and luxury is a big drawcard in both cases.

An American who lived in Europe started a business importing luxury prams into the US:

https://www.theguardian.com/news/2018/mar/20/bugaboo-luxury-...

Having pushed my share of prams, larger diameter wheels are a plus. But my favorite one for convenience was a folding "umbrella stroller" that I could shake open with one hand while holding a baby with the other.

I have a Britax Pathway stroller (https://www.target.com/p/britax-pathway-b-safe-35-travel-sys...), which looks like a monster, but literally push one button and the thing deploys; I did it several times today with the baby in the arms.

As well as the reasons you mentioned there is also perceived value for money. I suspect this trend is due to an interaction of psychological marketing and consumer preference.

Prams / strollers are not car seats.

Some places require kids to be in car seats until age 8. This is 2nd, 3rd, or 4th grade. These are not babies.

The manufacturers have lobbied for this "think of the children" law. Sales go up because parents are forced to buy the product. The manufacturers would be happy to raise the age even more.

1% of those kids are over 92 pounds. One can outweigh the mom, and can be asked to install his own car seat.

Maybe I'm missing something super-recent, but for second graders, a "cat seat" is basically a piece of plastic for them to sit on so that the seat belt passes on their chest, instead of neck, which would be disastrous in case of accident.

Unlike toddler car seat, these seats don't look huge by any means, compared to the kids sitting on them. (Well I guess it's still problematic to sit three of them in a row in most cars, but that's a separate discussion...)

The author of "Freakonomics" has a TED talk about this. It's a little old though (2005): https://www.ted.com/talks/steven_levitt_surprising_stats_abo...

Fear is not only the mind-killer, it's also the most powerful upselling strategy in the world. Particularly to young parents who tend to be a bit insecure about how much caring is enough. It's not just fear that something bad might happen to their child, it's also fear of being only the second-most responsible set of parents in the room.

Mostly safety because there is more focus on side impact protection. it leads to wider, wrap around designs.

I believe it is because they’re made of plastics which need more width to provide the same strength.

The narrower seats (I used Radians) all appear to have metal frames instead. And they weigh more!

I instinctively thought of high obesity rates in the US and other western nations.

For babys?

As others have said.... many jurisdictions in the US now require child seats well into the elementary school years.

Mostly boosters though, which aren’t really full fledged car seats. Washington requires car seats until 4 or so, and boosters until middle school.

It's for kids who haven't yet reached age 8 or a height of 4'9" (145 cm). That is the law. They could easily weight as much as their mother.

Washington state just changed their law. Now kids under 4'9" must use a booster up to the age of 16. Realistically, they have stated that 13 year olds will not be required to use a booster since, at that age, they are allowed to sit in the front seat anyway.

For a single seat, the size makes sense as you want to have cushioning on the outer walls. But there is no good reason not to have double and triple seats which only has thin separation on the inner boundary of the seats (even just having once the default padding vs. twice would be a big win).

So, if car manufacturers want to advertise "3 rear seats", they should be forced to offer child seating for 3 too.

Going to put in a plug for Diono Radian car seats [1]. We have a 4 year old and 2 year old twins. All three of them fit with these seats in the back of our Honda Civic.

They are amazing and definitely worth the premium, in my opinion.

[1] https://www.diono.com/us/product/radian-3rx/

Same. The 'compact' baby seat barely fits in our SUV!

I’ve seen the same in full-size suvs.

AS a parent with 2 young kids, the huge car seats fit fine in a generation 2 toyota prius. While not a tiny car it isn't wide.

Length-wise, our car seat only fits in the center of the back seat of our 3rd gen, and even then we have to push the front passenger seat so far forward that you have to be pretty small to fit in it. We could probably raise the seat a bit more if needed, though, but it's already fairly upright.

Bzzzzt, try again. I can fit both kids and carseats in the back of my old tiny 2 door VW GTI.

Hey, please make your point without being a jerk on HN. Your post would have been fine with just the second sentence.

https://news.ycombinator.com/newsguidelines.html

The Golf was always an unusually spacious car for its segment. Probably because of the more vertical hatch and a roof that's not so slanted as on most other cars. So the back seat can sit further back.

especially if it's an older one; of course there's more room!

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