"Passenger-miles" is the main sleight-of-hand
trick the airlines use to work their statistical magic, but it isn't the only gimmick in use; this from an air travel industry Internet page:
"The number of U.S. highway deaths in a typical
six-month period -- about 21,000 -- roughly equals all commercial jet air travel
fatalities worldwide since the dawn of jet aviation decades ago. In fact, fewer people have died in
commercial air travel accidents
in America
Here we momentarily drop the "passenger-miles" device in favor of what seem like a couple of straight
numbers-to- numbers comparisons; but on examination these, too, turn out to be impressive-sounding yet uninformative factoids. Maybe more people travel on highways every six months today than traveled by air in all those decades ("since the
dawn..."). Maybe there
are more automobile trips every three months now than there have been commercial air travel flights over the past 60 or 70 years. We don't get real
numbers. (Note also the language: people die in air travel accidents but they're killed in their cars.)
But it's the passenger-miles gambit that provides the basis for the most competitive comparisons the air travel industry makes. Here's another
quote from that Internet page:
"In the United States , it's 22 times safer flying in commercial air travel than driving in a car, according to 1993-95 study
by the U.S. National
Safety Council comparing accident fatalities
per million passenger-
miles traveled."
Why "passenger-miles"? Seen any 200-seat cars on the road? No, the automobile
figures are compiled at --
what? -- maybe two
or three passengers per mile? as compared to the airlines'
hundreds? Think how many more
individual trips highway travelers took -- the vastly greater number of opportunities for accidents they exposed
themselves to -- to rack up the same millions of miles. How many air
travel passengers would have
died (or been killed) in that number of trips?
But even if you
accept passenger-miles as a concept,
there's still the question of scorekeeping. One hundred
passengers fly 1,000 miles, at which point the plane crashes.
Sixty passengers die. Does the airline get 40,000
passenger-miles credit for the survivors?
No, "passenger-miles" may help the airlines figure their ROI or decide on
what type of equipment to buy
next, but as backup for safety claims -- that ain't
getting me out of my car. Let me know, better, when they develop
a jetliner that can coast over to the side of that
highway in the sky if its engines cut out, so you can ring up the aero club at the emergency callbox. You can improve your chances of surviving an auto accident
by wearing a seat belt.
What will your seat belt do for you if the view out the front window of your plane becomes cornfield?
# # #
I had referred to airline industry web pages as the
source, but I’m reminded now that it was primarily these newspaper articles,
although some websites figured into it later.
I can also now cite the names of the experts who
published the statistics I refute so decisively. They were H.W. Lewis, a
Physics professor, and Richard H. Wood, a professor of Safety Science. I
believe it was a coincidence that both articles appeared the same day, as there
doesn’t appear to have been a special section on safety in that issue of The
Times. I had written a letter to the
editor in 1980 that went nowhere, but the impetus to actually pursue the
subject came by way of the late Times columnist, Jack Smith, who touched on it in a column five years later.
Maybe the subject’s been debated someplace, but I’ve never
seen it done – a surprise to me considering the prevalence of bright minds much
better at mathematics and statistics than mine. That raises the possibility
that I could be talking through my hat, something I’ve been known to do – but I
don’t think so this time.
