this post was submitted on 01 Jun 2024
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xkcd #2940: Modes of Transportation

https://xkcd.com/2940

Explain xkcd #2940

Title Text:

My bold criticism might anger the hot air balloon people, which would be a real concern if any of them lived along a very narrow line directly upwind of me.

alt-text:A chart that categorizes various modes of transportation based on their practicality and danger level:

Zone of Practicality:

  • Trains
  • Airliners
  • Boats
  • Walking
  • Cars
  • Scooters
  • Bicycles

Zone of Specialty and Recreational Vehicles:

  • Motorcycles
  • Helicopters
  • Light aircraft
  • Go karts
  • Skateboards
  • Rollerblades
  • Skis
  • Unicycles
  • Sleds
  • Bumper cars

?????:

  • Hot air balloons

“Hot air balloons are the optimal mode of transportation, if your optimization algorithm has a sign error.”

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[–] [email protected] 7 points 6 months ago* (last edited 6 months ago) (2 children)

Sweden , a country of 10 million, we have about 150 people killed per year from car accidents

Yes, and how many die every year from plane crashes in sweden?

If we take a relatively big plane (450 passengers) as an example. One has to fall out of the sky every 3. Years to match the car accident number...

3186 deaths over 10 years VS 1.19 million every year.

(This is globally. Sweden and Norway(where i live) will naturally have pretty radically lower numbers then globally when it comes to road safety.)

But look at that air travel number again: 3186. Over 10 years. Globally. Commercial Air travel is fucking safe. Its horrible for the climate. But its safe.

Whatever way you slice those numbers it comes up air travel i safer. Feel free to find actual statistics that contradict me. :)

[–] [email protected] 10 points 6 months ago* (last edited 6 months ago)

I think I get what the guy is trying to say. Per journey, air travel might indeed end up being statistically less safe (how many times a year an average person flies vs. how many times they drive their car) but of course the question is whether that particular metric is any useful. Surely if you replaced all airplane trips with car trips, more people would die.

This Wikipedia article contains a table, which if true, confirms it:

https://en.wikipedia.org/wiki/Aviation_safety#Transport_comparisons

If you sort it by Journeys, you'll find that 117 people die in an airplane per billion journeys, while only 40 die per billion car journeys. But the article points out exactly what I said before.

Funny example that illustrates how important the choice of metric is, is the Space Shuttle which is statistically incredibly unsafe per journey (17,000,000 deaths per billion journeys) and even per hours (only skydiving coming first by a small margin) but is safer than bicycles and only twice less safe than cars per distance traveled because of those insane distances it covers in orbit.

Edit: Not that I do not know whether the table counts only commercial flights or all airplane/helicopter journeys. And also the statistics is pretty old (1990-2000) and only covers the UK, so you may still be right and commercial air travel in the last decade might be safer per journey than cars globally. Can't find a better statistics.

[–] [email protected] 0 points 6 months ago (2 children)
[–] [email protected] 4 points 6 months ago* (last edited 6 months ago) (2 children)

From your own source:

Since 1997, the number of fatal air accidents has been no more than 1 for every 2,000,000,000 person-miles[c] flown,[citation needed] and thus is one of the safest modes of transportation when measured by distance traveled.

So I guess this is the point you are trying to make?

[–] [email protected] 5 points 6 months ago

You can argue that "per person miles" is a better metric, but that is completely orthogonal to their initial claim.

[–] [email protected] 1 points 6 months ago (1 children)

Well, what I want to know is "Am I going to die today?". The distance traveled is irrelevant to answer that question. The only reason to add that to the equation is to make air travel look safer.

[–] [email protected] 2 points 6 months ago* (last edited 6 months ago) (1 children)

I honestly think you are showing a fundamental lack of understanding of statistics.

"Per trip" is a horribly poor metric. Because there is a fundamental difference between a trip down to the store, or a cross country trip, even with a car. Also it would be extremely dependent on where you are going, where you live etc. etc.

For the discussion to have any meaning you have to abstract it to a metric that makes sense for all people, or else you would have to also figure in where you usually travel, how good a driver you are etc etc etc.

At that point its a completely meaningless semantics exercise because for instance taking a plane to work is not realy valid for me since i live in the same city as i work... Or lets do it the other way around: If i need to go to Spain tomorrow, its safer for me to fly then to drive there. (This is based on your own sources)

[–] [email protected] 2 points 6 months ago* (last edited 6 months ago) (2 children)

But per mile measurement for flying implies that every mile of a flight is equally dangerous, but the truth I'd that it is most dangerous to start or land, which is a per trip occurrence. The take off and landing is equally dangerous whether you travel a long or short distance in between.

[–] [email protected] 3 points 6 months ago (1 children)

It's still a terrible metric to compare the safety of modes of transport and the Wiki article just below the table explains it well:

The first two statistics are computed for typical travels by their respective forms of transport, so they cannot be used directly to compare risks related to different forms of transport in a particular travel "from A to B". For example, these statistics suggest that a typical flight from Los Angeles to New York would carry a larger risk factor than a typical car travel from home to office. However, car travel from Los Angeles to New York would not be typical; that journey would be as long as several dozen typical car travels, and thus the associated risk would be larger as well. Because the journey would take a much longer time, the overall risk associated with making this journey by car would be higher than making the same journey by air, even if each individual hour of car travel is less risky than each hour of flight.

If people made similar trips with cars as they do with airplanes, cars would lose in the per journey metric big time.

[–] [email protected] 1 points 6 months ago (1 children)

Of course cars would loose if you tried to use it to travel across the Atlantic...

[–] [email protected] 1 points 6 months ago* (last edited 6 months ago)

If you are traveling across the Atlantic to get from Los Angeles to New York i would argue that you are traveling the wrong way...

[–] [email protected] 2 points 6 months ago* (last edited 6 months ago)

Yes, and?

The point of distance is to take it into aggregate, for both modes of transport.

This is in fact the exact point i am making.

Per trip measurement implies that every trip (regardles of time or distance traveled) has equal danger.

[–] [email protected] 2 points 6 months ago* (last edited 6 months ago)

Very interesting 🤔

And your point about metrics is pretty spot on.

In the end it becomes an exercise in trying to find the metric that best supports your argument.

We have also been jumping around a bit on geographical limitations. And in for instance Scandinavia, the original premise might be closer to real due to better road safety.

I think implying some sort of myth or ruse is missing the mark hard on this subject.