HOW LETHAL IS CYCLING, PART 2: Lies, damned lies, and Krygo"Facts"

In article ,
AMuzi wrote:

Tim McNamara wrote:
Living is lethal. The risk of death is 100%.

Yeah.
Although I've ridden more days, you probably have more
miles. According to r.b.t. data manipulation, we're both
already dead anyway.

Hmmm. That might explain a few things about recent events in my life.

In article fcf4a3c2-ce35-426e-bf2a-0d9588564147
@g10g2000yqh.googlegroups.com, says...
On Apr 9, 8:44*am, Andre Jute wrote:
On Apr 9, 6:26*am, mike wrote:





In article 5514624f-4c48-44f7-b99b-4bb1318355f4
@e7g2000yqf.googlegroups.com, says... On Apr 9, 4:55*am, Frank Krygowski wrote:
On Apr 8, 9:41*pm, Andre Jute wrote:

We've already determined, from a source supplied by Krygowski himself,
that per trip cycling is 11 times as lethal as motoring, and per mile
cycling is 2.9 times as lethal as motoring. If Krygo now no longer
wants to stand by those numbers, of course no one will be surprised..
To Krygo any number is good enough, and he'll stand by it for five
minutes before he throws out a new one. Half, double, ten time, ten
magnitudes, why should Krygowski care? All numbers are the same to
Krygowski.

Actually, these figures dont make sense as they would suggest that the
average cycle trip is more than 3 times as long as the average driving
journey. Could they have been reversed perhaps - with cycle trips 2.9
times as dangerous and 11 times as dangerous per km? In either case
though, if you accpt the figures as being ball-park accurate and include
Frank's 1/5000 risk of dying in a car, it suggests the risk while
cycling may be between 1/2000 and 1/500 for a keen cyclist - per annum
(ouch!!).

Mike

You're right, the numbers got switched. Sorry. Here is the correct
text:

MEASURED PER JOURNEY, CYCLING IS
2.9 TIMES MORE DANGEROUS THAN RIDING IN A CAR.

MEASURED BY DISTANCE TRAVELLED, CYCLING IS 11 TIMES MORE DANGEROUS
THAN RIDING
IN A CAR.

I would beware of Frank's 1 in 5000 number. Suspicion has been thrown
upon it already by the irrational and erroneous company it keeps, and
its internal consistency is poor, for instance it seems to forecast
61,200 automobile deaths when we would be expecting around 37,000; we
don't know precisely what it includes. Now's my sleeping time,
followed by my riding time, but in twelve hours or so I'll deconstruct
the rest of Kreepy Krygo's wretched table, and his other
pronouncements as well.

Andre Jute
*Never more brutal than he has to be -- Nelson Mandela

PS: I'd say "ouch!" is right, but as a "per annum" rate, that would be
a massacre of cyclists not seen since the Roman circus. There's
something fundamentally cookie about Krygowski's numbers, and I don't
just mean his wild-eyed, unsupported, swingeing pronouncement. -- AJ

A quick check on some reasonably sensible looking web-sites suggests
that as of 2008 the chance of dying in a car accident each year was
approximately 1/8300 in the US, 1/11000 in NZ and 1/20000 in the UK.
Although we still lag behind Europe (here in NZ) things havew improved
since the early 70's when we had a horrific 1/3500 risk. Assuming some
sort of status quo in road technology, driving conditions, social values
etc (which is unlikely in practice) this would suggest that the chance
of cause of death for any randomly selected individual to be a result of
car accident is approximately 1% in the USA and ~0.4% for UK (over a 75
year life expectancy). If cycling is considered ~10 times as dangerous
per km, but also assume that a typical keen cyclist rides perhaps 1/3
the distance that a typical driver drives, and only keeps up that up for
half their life, then the keen cyclist has approximately 1.5% chance of
meeting his/her maker while on the saddle. So, although cycling is
clearly risky at times (I have a bone to pick with a truck-trailer unit
that gave me less than 40 cm clearance this morning - while heading into
an inside turn), the amortised risk-over-life isn't all that different,
in absolute terms, to the risk of death while driving (and is much less
than the risk of death as a direct result of obesity, smoking, alcohol
cosumption etc).

So on reflection, I don't think it is quite time for me to give up life
on the wheel yet.

Andre - does the above back-of-the envelope estimation provide with a
hint of the answer you are looking for?

Mike

Mike:

I've already published my conclusions (IS CYCLING SAFE? --
http://groups.google.ie/group/rec.bi...f2a96d4?hl=en#
) and also an executive summary -- that's a euphemism for "short
version for cyclists with a very attention span" -- that summarizes
only the cyclist's risks compared to those of the motorist (THE RISK
OF A CYCLIST DYING ON THE ROAD: THE EXECUTIVE SUMMARY
http://groups.google.ie/group/rec.bi...f01375e?hl=en#
).

So here I give only quick notes. Perhaps, if you want to continue
this, you would do so in one of those two threads as all the others in
the series have been contaminated by Krygowski's malicious
interference and attempts to keep "ownership" of cycle safety firmly
in his own hands.

This is a conversation between Mike and Andre, with Andre starting
he

We've already determined, from a source supplied by Krygowski himself,
that per trip cycling is 11 times as lethal as motoring, and per mile
cycling is 2.9 times as lethal as motoring. If Krygo now no longer
wants to stand by those numbers, of course no one will be surprised.
To Krygo any number is good enough, and he'll stand by it for five
minutes before he throws out a new one. Half, double, ten time, ten
magnitudes, why should Krygowski care? All numbers are the same to
Krygowski.

Actually, these figures dont make sense as they would suggest that the
average cycle trip is more than 3 times as long as the average driving
journey. Could they have been reversed perhaps - with cycle trips 2..9
times as dangerous and 11 times as dangerous per km? In either case
though, if you accpt the figures as being ball-park accurate and include
Frank's 1/5000 risk of dying in a car, it suggests the risk while
cycling may be between 1/2000 and 1/500 for a keen cyclist - per annum
(ouch!!).

Mike

You're right, the numbers got switched. Sorry. Here is the correct
text:

MEASURED PER JOURNEY, CYCLING IS
2.9 TIMES MORE DANGEROUS THAN RIDING IN A CAR.

MEASURED BY DISTANCE TRAVELLED, CYCLING IS 11 TIMES MORE DANGEROUS
THAN RIDING
IN A CAR.

I would beware of Frank's 1 in 5000 number. Suspicion has been thrown
upon it already by the irrational and erroneous company it keeps, and
its internal consistency is poor, for instance it seems to forecast
61,200 automobile deaths when we would be expecting around 37,000; we
don't know precisely what it includes. Now's my sleeping time,
followed by my riding time, but in twelve hours or so I'll deconstruct
the rest of Kreepy Krygo's wretched table, and his other
pronouncements as well.

Andre Jute
*Never more brutal than he has to be -- Nelson Mandela

PS: I'd say "ouch!" is right, but as a "per annum" rate, that would be
a massacre of cyclists not seen since the Roman circus. There's
something fundamentally cookie about Krygowski's numbers, and I don't
just mean his wild-eyed, unsupported, swingeing pronouncement. -- AJ

I've now disposed of Krygowski's numbers in various other posts.
Krygowski fell over himself to accept some interim numbers I suggested
while I spiralled in on a set of mutually supporting numbers. The
upshot is that, while Krygowski has been running around saying cycling
is about twice as safe per annum as motoring (without being willing or
able to give a source), the actual figure once you define the universe
of cycling correctly is nearer four. I've also disposed of some of
Krygowski's other wild-assed guesses and wishful numbers, like a
cyclist standing only one chance in 130,000 of dying on the road, the
sort of stupidity which throw all cycling advocacy into disrepute.

A quick check on some reasonably sensible looking web-sites suggests
that as of 2008 the chance of dying in a car accident each year was
approximately 1/8300 in the US, 1/11000 in NZ and 1/20000 in the UK.

That accords very closely with what I discovered when before
publication I checked my own numbers (which are all for the States)
for consistency and general application ot anglophone countries. For
instance, in Ireland the chances of dying in a car accident are also
1/20,000. In the States the netsite you found reports 1/8300 which is
not so far from my conclusion of 1/9750 and what is outside the
margins of error is easily accounted for by small differences of
definition and inclusion. For instance, your number clearly includes
non-motorists who die in car accidents while mine includes only those
travelling in internal combustion-driven vehicles, shorthanded as
"motorists". My interest here is: Are you more likely to die because
you ride a bike or because you drive a car?

Although we still lag behind Europe (here in NZ) things havew improved
since the early 70's when we had a horrific 1/3500 risk.

I lived in Australia in the early 1970. I thought nothing of averaging
a ton outta Adelaide into Darwin, and back without sleeping after a
short meeting. I doubt our American friends can even even imagine the
unpaved road on which I did it (or even how far it is), or the
cattetrains travelling at 90mph that one has to pass. Every time I did
it, a Falcon GTHO was returned to the leasing company dying of thermal
overload, limping on never less than three broken dampers.

Assuming some
sort of status quo in road technology, driving conditions, social values
etc (which is unlikely in practice) this would suggest that the chance
of cause of death for any randomly selected individual to be a result of
car accident is approximately 1% in the USA and ~0.4% for UK (over a 75
year life expectancy). If cycling is considered ~10 times as dangerous
per km,

The figure of 11 I've been quoting seems pretty solid to me,
considering the correspondence with other figures I some confidence in
once we reduce it to risk per hour on the bike.

but also assume that a typical keen cyclist rides perhaps 1/3
the distance that a typical driver drives,

I'm not so sure. We have good figures from the DoT which puts the
average American's motoring at 14,400 miles per annum. I just don't
see "a typical keen cyclist" doing one third or 4800m/7750km per
annum. There are about half a million regular commuters in the States.
Even for one of them that would be a trip of 11 miles each way to and
from work each, assuming 220 workdays and assuming they are all year-
round commuters (loud guffaws from Chicago and points north). I don't
buy a 22m round trip for half a million people, or even a substantial
part of them, for even part of the year. Or a roadie who rides 48
weeks in the year (already stretching it) would have to ride 100 miles
in each of those weeks. I don't buy it, Mike.

and only keeps up that up for
half their life, then the keen cyclist has approximately 1.5% chance of
meeting his/her maker while on the saddle.

An American cyclist, by my final estimate (all demographically sampled
statistics are *estimates* -- something the more passionate cycling
advocates should respect) has a 1/36000 chance of dying on the road
this year, his motoring counterpart 1/9750. I really don't see why
most people shouldn't cycle as long as they can motor, say for about
60 years. That's a lifetime chance of dying on the bike of 0.17 per
cent, about one tenth of the 1.5% you arrive at. The motorist's risk
is 0.62 per cent, almost four times higher. The motorist's risk is
aggravated by the health risks of sedentary motoring which your
ameliorate or avoid by taking exercise on your bike, but you're both
at greater risk from a good spread of other factors than from
transport.

So, although cycling is
clearly risky at times (I have a bone to pick with a truck-trailer unit
that gave me less than 40 cm clearance this morning - while heading into
an inside turn),

Urgh!

the amortised risk-over-life isn't all that different,
in absolute terms, to the risk of death while driving (and is much less
than the risk of death as a direct result of obesity, smoking, alcohol
cosumption etc).

You're right, even with my more correct numbers substituted. The
difference between .17 and .62 per cent chance of dying on the road
over a whole life isn't much chop in an actuary's outlook, though no
doubt cycling advocates will be dancing around hysterically foaming at
the mouth with glee that I've discovered cycling is four times less
likely to kill you on the road than motoring.

So on reflection, I don't think it is quite time for me to give up life
on the wheel yet.

Understatement of the year.

Andre - does the above back-of-the envelope estimation provide with a
hint of the answer you are looking for?

Oh, definitely, once I've applied the corrections. I'm happy to have
your case to apply my newly firmed-up numbers to. I only wish I'd
thought first of the reducing the numbers to a lifetime risk.

Mike

Thanks for your input, Mike.

Andre Jute
Visit Jute on Bicycles at
http://www.audio-talk.co.uk/fiultra/...20CYCLING.html