4 ms·

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

nitrogen 6y ago
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.
- jbay808 6y ago
  I know; I've had the same experience. :( It's a shame. The pedestrians will have to find a way to get taller too.
  - globular-toast 6y ago
    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.
globular-toast 6y ago
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.
- tpmx 6y ago
  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?
  - JoeAltmaier 6y ago
    To an amazing degree. In the limit, the large vehicle proceeds nearly unimpeded and the small one is a ball of tinfoil.
    - tpmx 6y ago
      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.
      - JoeAltmaier 6y ago
        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.
  - Marsymars 6y ago
    > 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.
    - tpmx 6y ago
      It's hard to disagree with physics. However, please read what I wrote here: https://news.ycombinator.com/item?id=23694479 https://news.ycombinator.com/item?id=23694479
  - elihu 6y ago
    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.
- ajzinsbwbs 6y ago
  Is that really true? If two big cars hit each other there’s a lot more energy in the collision than two small cars.
- jbay808 6y ago
  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.
- Marsymars 6y ago
  > 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.

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.

jbay808 6y ago
I know; I've had the same experience. :( It's a shame. The pedestrians will have to find a way to get taller too.
- globular-toast 6y ago
  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.

globular-toast 6y ago

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.

tpmx 6y ago
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?
- JoeAltmaier 6y ago
  To an amazing degree. In the limit, the large vehicle proceeds nearly unimpeded and the small one is a ball of tinfoil.
  - tpmx 6y ago
    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.
    - JoeAltmaier 6y ago
      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.
- Marsymars 6y ago
  > 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.
  - tpmx 6y ago
    It's hard to disagree with physics. However, please read what I wrote here: https://news.ycombinator.com/item?id=23694479 https://news.ycombinator.com/item?id=23694479
- elihu 6y ago
  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.
ajzinsbwbs 6y ago
Is that really true? If two big cars hit each other there’s a lot more energy in the collision than two small cars.
jbay808 6y ago
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.
Marsymars 6y ago
> 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.