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Comment by JoeAltmaier | Hacker News Reader

Drive the largest vehicle you can. When in a collision the momentum is converted to crushing force, you want to be in the less-crushable vehicle.

Hey this may be an unpopular choice, but it is the one with the biggest safety impact! And that was the question.

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Rather immoral. Not just offloading, but also exacerbating the burden onto others.

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

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

The free preview of your citation seems to propose legal liability for drivers of vehicles that cause outsize risk to others.

Safety equipment inside cars does the same -- people who feel more safe in their car drive more dangerously and take more risks. Maybe that's addressed in the full article.

It's the arms race itself (and the fact that we allow it to continue) that's immoral. Acting rationally within the arms race is not immoral. Our laws should address the core causes of this arms race.

People are starting to wake up to the notion of "systemic issues," but still too slow to apply what they've learned about that topic to other matters. It's a mistake to focus on the behavior of individuals in a system that's sanctioning and encouraging bad behavior.

My buddies and I all subscribed to this theory as young kids in Texas, then one time some of us did a trip to the junkyard to get some parts and it was a graveyard of absolutely demolished pickup trucks. Shook us pretty good. The junkyard guy knew what happened to some of them, too, like this one where the passenger compartment was just a block of near solid steel apparently got in a crash with a Camry.

So I'm not sure "big car safe" is necessarily true.

Correction: you want to be in the vehicle with the most crushable distance of material. That way the force is spread out more over time and there's less going through your body at any moment.

That’s not the entire story. If you value your health over that of all others, you will want to crush the car the others are driving in over its full length before the crushing of the parts of your own car where you are sitting starts.

That’s where having the sturdier car can help.

You also will want to be in the car that decelerates less briskly. That’s where, in collisions with movable objects, having the heavier car helps.

A heavy car without crumple zones from the 1950s that could kill you when hitting a wall at 20 km/hour might still be the safer car in a head-on collision with a much smaller car with a few meters of crumple zone (cars from the 1950s were incredibly unsafe, so I think this would require extra-ordinary circumstances)

I'm trying to be careful how I type this, but the point of crumple zones isn't just to make the car stop slower, but to keep parts of the car you really don't want to crush from crushing.

If you crash into a wall at 20km/hr, it's a lot better if the engine bay gets smashed up, than if the compartment you're in collapses around you.

Given enough mass, you won't experience any noticeable deceleration during a collision! https://www.youtube.com/watch?v=hWToJxKYRSc

My Kenworth will crush your F350, X5, Tahoe, or whatever other big ass truck/SUV you can get.

So if you really want to reign supreme on the road you ought to get a semi truck, with a sleep cab you convert it to seating for the kids too.

Is this the end game of suburban families race to owning the biggest hunks of steel on the road?

Reminds me of this:

https://www.autoexpress.co.uk/volvo/xc90/103233/no-fatalitie... (2018)

"No fatalities ever recorded in a Volvo XC90 in the UK - Analysis of official figures finds no driver or passenger fatalities have been recorded in Volvo's XC90 since records began in 2004"

Volvo XC90 is a relatively popular SUV there, and for the UK, quite large.

"Around 70,000 XC90s have been sold in the UK since the original model launched in 2002"

I would guess the magic here is:

a) the car is designed with safety as the number 1 design criterium (it's a Volvo)

b) it's quite large (lots of crumple zone mass)

c) it's probably not driven at insanely high speeds by young male drivers with poor impulse control very often.

I propose an alternative.

Start including the effect on other cars in crash tests.

In other words, yeah, if I drove a frickin' monster truck, yes, it's going to be extremely safe for me, but it's absolutely deadly to anybody in a sedan. So that monster truck should get low crash test scores.

Your answer merely creates an arms race of larger and heavier cars.

Only if everyone can afford them, which isn't true. Its more like, creates a class system where the rich are safer. Which is already the case to be honest.

A sad truth.

This has had little to no real evidence in specifics to SUVs. Plus it increases the risk on others, which is something one should have to realize.

Pluuus, Larger vehicles suffer from worse handling, worse braking distances and higher accident rates. It's all just dumb.

if you defect you get a bigger payoff than if you cooperate!

It's definitely not an unpopular choice, since SUV sales are skyrocketing

Presumably downvoted because people don't like it. But it's the truth.

> A 2700lb subcompact vehicle that scores Good may fare worse than a 5000lb SUV that scores Acceptable. This is because the small overlap tests involve driving the vehicle into a fixed obstacle, as opposed to a reference vehicle or vehicle-like obstacle of a specific weight. This is, in some sense, equivalent to crashing the vehicle into a vehicle of the same weight, so it's as if the 2700lb subcompact was tested by running it into a 2700lb subcompact and the 5000lb SUV was tested by running it into another 5000 lb SUV.

Its the "truth" until you run into something that's bigger than you.

No.. that still shows it's the truth.

This isn't correcting for whether people can safely drive the biggest vehicles on the road, semi trucks.

It's the "let's defect in a prisoner's dilemma" strategy that works great until others use it too.

I've been riding out the quarantine in a less populated area, and I am surrounded by trucks so tall that the driver can't even see the roof of my car if I am stopped next to them at a light. It's already too late to avoid defection -- if I stay here for good, I will have to get a taller car just so other drivers can see me and so I can see through the windows of parked cars when turning.

I know; I've had the same experience. :(

It's a shame. The pedestrians will have to find a way to get taller too.

Pedestrians have no place on the road, just like cyclists. They aren't people, they are obstacles. It's going to take a huge reform to change that, especially in the US.

It is not the prisoner's dilemma at all. If everyone gets big cars then everyone is equally as safe. They don't all die.

For crying out loud, people, I know it's stupid, I know it's wrong, but it's the truth. It's an uncomfortable truth that your downvoting will not change.

I think you're on to something.

First: there's vehicle-to-barrier crashes (think trees, etc):

Having a vehicle with a large well-designed crumple zone seems obviously good from a survivability POV.

Second: there's vehicle-to-vehicle crashes:

Is it really a zero-sum game? If a small car crashes head on with a large car, will the people in the small car suffer worse than if they crashed into another small car? To what degree?

To an amazing degree. In the limit, the large vehicle proceeds nearly unimpeded and the small one is a ball of tinfoil.

I mean, that makes sense if we assume that cars are sphere-shaped with consistent density. Of course, they aren't.

I guess what I was looking for was actual data, not assumptions.

Data? My son in his Ford F350 had a collision with a compact car that pulled out directly in front of him across the highway at speed. Small car: totalled. Truck: some scratches on bumper, loud noise.

> Is it really a zero-sum game? If a small car crashes head on with a large car, will the people in the small car suffer worse than if they crashed into another small car? To what degree?

Well it's zero sum in the linear sense as the relative total velocity change is the same, but crash survivability isn't linear. Rather, it decreases exponentially, since kinetic energy is proportional to the square of velocity - so a head-on crash between a semi and a compact car subjects the occupants of the compact car to nearly 4x the force that they'd be subjected to if they crashed into another compact car.

It's hard to disagree with physics.

However, please read what I wrote here:

https://news.ycombinator.com/item?id=23694479

If a heavy car collides with a light car head on at, say, 60mph, the heavy car might slow to 20mph whereas the light car might be pushed backwards at 20mph. So one car experience 40mph of velocity change in a short time interval, whereas the other experience 80mph of velocity change.

This is hypothetical; I don't know what real numbers from real collisions are like, but light cars are definitely at a disadvantage in that they can get knocked around a lot more. There's also the possibility of a light car getting pinned between a heavy car and an immovable object or another heavy car.

I don't think this is zero-sum: ideally, we'd all be driving around in large bubbles that weigh 200 pounds or less and have huge crush zones filled with styrofoam or something.

Is that really true? If two big cars hit each other there’s a lot more energy in the collision than two small cars.

It is a prisoner's dilemma.

When you all have big cars, you're back in an equilibrium where everyone seems as safe in head-on collisions as the equilibrium where everyone drove small cars. But each car now has way more kinetic energy and momentum, and needs bigger crumple zones to absorb it (oops! You won't find room to expand those in side collisions!), is more prone to rollover, has less visibility of pedestrians, bicycles, and children playing in your driveway, worse gas mileage, more pollution, less parking space, etc.

And then someone decides to get an edge over the crowd by driving a monster truck and you're back to scrambling into a new, even worse equilibrium.

> It is not the prisoner's dilemma at all. If everyone gets big cars then everyone is equally as safe.

All the pedestrians and cyclists they mow down are less safe though.

And everything becomes more polluted, which is presumably also not equally safe.

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