xkcd #2940: Modes of Transportation
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.”
From your own source:
So I guess this is the point you are trying to make?
You can argue that "per person miles" is a better metric, but that is completely orthogonal to their initial claim.
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.
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)
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.
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:
If people made similar trips with cars as they do with airplanes, cars would lose in the per journey metric big time.
Of course cars would loose if you tried to use it to travel across the Atlantic...
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...
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.