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Comment by Intermernet | Hacker News Reader

I recently flew ANA and they advise all passengers to keep their seatbelts on at all times when seated. It seems like simple advice. I do the same thing when I'm driving. I don't find it uncomfortable in the slightest, even sleeping. Maybe others have a different experience, but turbulence isn't that rare. I've had serious turbulence on many flights. Probably the worst was final approach / landing in Frankfurt with perfectly blue skies. The atmosphere does weird things.

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Every single airline says this for the last 15 years at least.

On some routes you see lots of loose seatbelts (Middle East, Africa). On European flights, everyone has the seatbelt on for the entire flight.

This behavior is reflected in car attitudes too. Many Japanese drive with a detached seatbelt. Not even the presence of children changes this calculus.

Wat? That seems out of character. Class related?

Actually that seems very Japanese in a weird way - they might be trusting themselves and everyone else to follow rules precisely, thus avoiding all the accidents and obviating the need for seatbelts.

Is driving actually kind of easy in Japan for this reason? I’ve never had a car while there. It’s wild how different Japan and China are despite being neighbors. I can’t think of a European neighbor pair that is so different.

One is an island nation that's been fairly open, the other had waves of isolationism, famines, and only recently opened up their markets in the late 80s. Private car ownership was not on the table until probably 25 years ago.

But to play your game, Switzerland and Italy, especially southern Italy, are very different.

Your counterexample is not even close to being accurate. Italy and Switzerland have much more in common than China and Japan. Italian is even one of the official languages of Switzerland. Switzerland and Italy are both essentially federations of distinct provinces. Both are recognizably Western European. China and Japan are worlds apart, as are China and India.

My main point was that there's plenty of reasons for China and Japan to be different, especially when it comes to driving norms. Are you surprised as the other poster was about these differences between China and Japan?

And going back to the original intent: would you say driving in Zurich and driving in Naples are two distinct experiences?

I can: Germany and (European) Russia. They are about the same distance as Tokyo to Shanghai. They have wildly different driving cultures! Also, China is the size of a continent. Did you drive in all the different regions? I doubt it. Do what region are you extrapolating from?

When I visited, Austria-Hungary were very different. So were Germany-Poland. And let's not even talk about Finland-Russia.

I mean, Europe had an iron curtain for decades and that shows at the boundaries.

Ahh.. a bit too trusting to the point of individual risk in a high trust society.

Most Dutch people don’t wear a helmet when riding a bicycle. As e-bikes are becoming more popular, some older people are opting to wear a helmet since the speed is higher, but many still don’t.

It’s not uncommon to see a parent riding around with a kid attached to the bike and neither are wearing a helmet.

I think it is kind of a cultural thing as well as convenience. If you ride a bike to the station to catch a train, then you might need storage or to carry it with you.

Also it's just not really a big danger. There's no epidemic of brain injury due to this.

Part of the reason is that because bike usage is so common and the infrastructure is very separate (bike lanes everywhere, no mixed traffic on eg roundabouts), and bikes almost always have right of way and are not to blame in an accident, that drivers are very aware of them. I noticed in countries like Ireland with much less bikes that bike lanes sometimes just end in the middle of a high speed roundabout. And most drivers there have no clue which is in part because until 10 years ago you could just buy a driver's license at the post office. It was a "learner's permit" but it was normal practice to just go and drive.

So yeah in Ireland I wouldn't even ride a bike with a helmet. In Holland I'm much safer even without one.

I don't remember the "Not Just Bikes" YouTube video, but he specifically discusses the relatively low rates of bicycle helmet wearing, especially amoungst urban riders. I agree with you: When there are serious bike injuries, it is usually due to a car or truck in mixed space. When only bikes riding less than 25km/h, the injuries are pretty minor.

Pricesely this, yes. And for the kids, an average trip to school takes like 5-10 minutes, hassling with three helmets (mine and of two kids) takes almost as long. And then I have to carry three helmets if I want to drop by to the supermarket after getting them to school.

The bicycle seats for kids are designed in such a way that the only real danger of a head being hit is in the frontal collision, or in a really forceful side one. The design of Dutch streets makes the chance of either happening small enough that the helmets are widely seen as not worth it.

Why is this downvoted? Please explain. It seems like a reasonable comment to me.

I thought that Dutch parents put small kids on the front of their bicycle to absorb the blunt of impacts. Then you dispose of the small child and make another one.

This really isn’t a similar comparison, Dutch infrastructure is built to prioritize making cycling safe at every decision point.

Whereas you’d be someone with a death wish to be riding without a helmet in most places in the US.

This is an asia thing, not a Japan thing. Saw this in most of South East Asia.

Loose seatbelts are probably fine. That’s what I do. Presumably that keeps me from getting launched into the ceiling. A lap belt is a compromise anyway. Aircraft crew use more as do car drivers for that matter.

Right but what's the point? If the belt is on very loose, you give your body a chance to gain momentum, which will be redirected when the seat belt catches you, which would lead to serious injury.

The belt doesn't need to be on tight, but it should be relatively snug.

It's just one of those things that is trivial to do, with a very, very low probability to save you from injury, but costs nothing, so why not...

You're going to the very extreme end of what he meant by "loose"...

I'm going by the levels of "loose" I regularly see on flights. I regularly see seat belts buckled, effectively fully slacked. It's not everyone, but probably 5%.

I'd rather redirect my momentum into soft webbing spread across my lap, than into my head impacting an overhead bin.

You won't gain additional momentum from a loose belt. But a loose belt may give your body the chance to slip out. The impulse you feel from a tight belt will be no less than the impulse you feel from a loose one.

>The impulse you feel from a tight belt will be no less than the impulse you feel from a loose one.

I don't see any interpretation of that that makes it true.

Impulse is constant, its the force that is transferred to your body. This is constant whether or not a belt is worn.

A belt simply takes that force and redistributes it into the seat frame, if the belt is not worn the force is not redistributed by the belt but rather by your head into the overhead bin

It's like debt. If I'm standing on the ground, I'm constantly "making payments" to the ground. If I jump off a cliff, then while I am falling, I stop making payments, so when I next contact the ground, accumulated debt suddenly must be paid.

More precisely, while I am falling, my velocity and consequently my momentum relative to the Earth steadily increases, which is analogous to debt because I will eventually need to restore the situation in which my momentum relative to the Earth is zero (because that is how people live their lives: at rest relative to the surface of the Earth rather than for example in orbit).

In the same way, the passenger in the airplane must eventually go back to being at rest relative to the airplane, but if the seat belt is very loose, "debt" (momentum relative to the airliner) can be accumulated before all the slack has been taken out of the seat belt.

Yes, the total amount of impulse (change in momentum caused by the environment's pushing on the person) integrated over time is the same regardless of how tight the seat belt is, but it matters whether that impulse is spread out over time or comes in one big jolt.

That doesn't make sense. Force is not accumulated by people standing on the ground, so your later analogy does not work at all

The ground opposes the force produced by gravity, there is no accumulation of anything. Gravity accelerates mass when it is pulling it in motion unless there is an equal and opposite force which is the normal force exerted by the ground (or airplane)

The impact is a matter of energy, not of force- if the force applies for more than an instant, you keep accelerating before hitting the ceiling and the energy of the impact will be proportional to the square of your speed. If the belt is tight, you stop at a lower speed (relative to the aircraft) and the energy of the impact (with the belt, in this case) is lower.

I disagree, a tight belt will cause the least amount of injury. Look at fall arrest systems.

If you're harness is loose, or your line is slack without an energy absorber, it'll break your back when you fall!

I've never been on any airplane where they didn't say you have to keep your seatbelt fastened at all times when seated.

I've been flying for a long time. It's only in the last decade that I've noticed the specific language of "keep your seatbelt fastened even if the light turns off". It's always been a "soft" suggestion, but it's becoming stronger, and repeated. The ANA flight crew in particular were quite adamant about it.

This may just be me becoming more aware of it, but, if so, I'm also becoming more aware of more passengers actually heeding the advice. I remember, not that long ago, most people removing their seatbelts as soon as the light went out. Not so common now.

> It's only in the last decade that I've noticed the specific language of "keep your seatbelt fastened even if the light turns off".

It makes you wonder why they ever even turn off the seatbelt light. Just keep it on the whole time, just like the equally anachronistic no-smoking light.

I feel like the light is just there to mollify the older generations who didn't grow up with mandatory seat belts wearing in cars, fought those laws loudly, and are still bitter that the government makes them take a sensible safety precaution. Are there enough of those people still flying that it makes sense to keep that light in use?

The seatbelt light nowadays is mostly a don’t move around sign.

During take-off and landing, it is. At cruise altitude, it really does mean "the pilots are expecting turbulence and suggest you stay seated", at least in my experience.

Of course they don't always get it right both ways: Sometimes reports of turbulence ahead turn out to be false positives, and at other times, strong turbulence can happen without any warning.

I've been on smoothe flights where the sign was kept on practically the whole time. Unfortunately I suspect some pilots forget about it, and I have observed that the public have gotten used to getting up to use the bathroom even when the sign is on (excluding takeoff and landing). I haven't flown enough to notice a pattern with specific routes or airlines.

There are times when the pilots are expecting turbulence, when they are notified by ATC or other planes ahead of them. During that time, the light means passengers shouldn't use the lavatories.

>Are there enough of those people still flying that it makes sense to keep that light in use?

There are entire states in the US that take that approach. Live free or die and all that.

So free.

>There are entire states in the US that take that approach.

Which ones? Rust belt? Flyover zone (or some such term)?

A "stay in your seat" light would be an improvement.

That's a good point! They even have a design for that on the bathrooms already (and now I wonder if that's always been the case, or if there was a time when people were frantically searching for the seatbelts there when the chime came on :)

> It makes you wonder why they ever even turn off the seatbelt light.

To tell you when it's relatively safe/not so safe to use the bathroom.

I've just browsed some old safety videos on YouTube, and in the U.S. this recommendation seems to have appeared in the early 90s (e.g. Northwest 1993 https://youtu.be/rUQtG0a_7d0?t=127), while being absent in the late 80s (e.g. Pan Am 1988 https://youtu.be/m3zj-oUm7vc?t=33).

I find sleeping on a plane more comfortable with a seat belt on actually. I hook my thumbs into it and it gives me more support for my hands and arms.

Might not be great for my thumbs in that kind of situation though...

I’ve flown internationally for a decade and it was only around 2018-20 I noticed most airlines reminding you to keep your seat belt fastened. Before that it seemed like the exception, not the rule.

Yep. Always have my seatbelt on. I am used to it.

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