Personally when enter a vehicle and start a trip, I'm interested in arriving at the destination alive, regardless of distance. If something bad happens, whether I die 1km into it, or 10.000km into, is quite pointless. So incidents per trip probably conform better to how people evaluate travel risks.
So for example with flights - I'd imagine the most dangerous parts are the take-off and landing - which happen once per trip no matter how long you fly for inbetween.
So for flights incidents / kilometer are perhaps misleading.
If you really start including risk factors you'll never stop, the risk is proportional to many other factors as well:
1) Time of day: Time of day factors in probably for both flying and driving at varying degrees
2) Where: In the US, which state you're driving in matters significantly for driving fatality rates
3) Day of week: Driving on weekends is more dangerous than driving during the week, doesn't seem to affect flights
4) ATC is a variable for flight accidents but not drivers
5) Flights might actually carry more risk per mile in certain situations: Flying over the oceans, eg
A truly correct apples-to-apples comparison would be so hyper-specific as to be useless.
Yet I suspect the people in twin towers weren't included in airline death stats.
Sure there isn't a perfect single metric - just pointing out that the one the airlines prefer appears to be biased towards air-travel.
The other factor that is often ignored is the issue of control. As a passenger of an airline you have very little impact on the chance of an accident - you are just an accident statistic.
Whereas if you are driving, your own driving behaviour, choice of car, route etc puts you more in control of the chances ( though of course by no means completely ).
This has a big impact on the perception of risk ( as more than average think they are better than average :-) ).
When comparing a difference of 1000x, sure its probably safer.
Your premise is wrong though, it isn't common sense to take a generalized statistic like deaths per km and extrapolate that to be the correct estimate for any particular trip.
The statistic loses all context of differences in vehicles, road conditions, time of day, specific roads, etc. The stat is a great example of how a statistic seems meaningful to get a big picture but is completely useless to us as we can't make any decisions based on a number that is so generalized as to lose all context and meaning.
Assuming that the survival rate is constant as a function of trip length, the empirical estimate of the risk is fully determined by the number of deaths per distance.
Airline travel is much riskier in takeoff and landing phases. A bunch of 200 mile flights is riskier than a 3500 mile trans-con trip.
Car travel is much safer on controlled access highways than 40 mph surface streets.
That's an assumption that doesn't hold up, at least that's the argument I was trying to make above.
Generalizing so much data down to a single statistic makes the number useless. Almost all context is lost, really the only context kept is mode of transportation and distance traveled. That isn't enough to help anyone make a decision for any particular trip.
I think I fly on average a bit more than once every two weeks. I'm in a car about every day, mostly for short trips--in the last month I probably spent about as much time in a car as in a plane. Pilots probably fly more hours than they drive.
You really have to fuck with the statistics to get driving to come anywhere close to commercial aviation in terms of safety, they're so far apart.
You can't influnce that when you fly.
Source?
> You can't influnce that when you fly
Whether you can influence a variable doesn't change its order of magnitude. Unless you're driving on a closed track at low enough speeds that if you pass out you'll be fine, you're safer flying than driving.
Look at accident reasons in the statistics. Velocity is a big part.
Changing the variable doesn’t change the overall order of a magnitude but the personal one.
If you don’t DUI your risk of dying because of DUI is lower
In theory it would be possible to create a safe driving car that would avoid unsafe roads, conditions, mental state, amount of driving, driving practices, speeds, distances etc. But a lot of the time it would just end up not being compatible with the road system and owning a car. And it still wouldn't totally prevent an accident, especially not caused by anyone else.
As someone who does both, the former is still controlled in a way we just don't do for cars.
Note that the moment we go to countries that are actually willing to take people's driver's licenses (and put them in jail when they drive without one, the way you'd expect to be treated flying a plane unlicensed), the safety statistics change. The only way we're getting that in America, however, is with self-driving cars.
But if someone is going on a 10,000km trip and trying to choose between modes of travel, the mode with the fewest incidents per mile will be the safest way.
(Complications like takeoff and landing might actually make a 10 mile commercial flight riskier, but that isn't an actual option. The 500 mile flight is going to work out safer in almost all circumstances though)