On 7/30/2014 10:33 AM, jbeattie wrote:
On Tuesday, July 22, 2014 7:52:29 PM UTC-7, Frank Krygowski wrote:

It takes only a little knowledge and skill to make cycling
_tremendously_ safe.

Riders should be skilled and knowledgeable, but in my experience,
there is a low correlation between injury and knowledge/skill level.
Looking at my cohort, all have been injured -- some seriously -- and
all are knowledgeable, experienced, skilled, brave, clean, trustworthy,
etc., etc. The idiots remain surprisingly unhurt -- like the idiots
running lights and riding the wrong way on one-way city streets on my
way home last night. It reminds me of working ambulance and finding that
the drunk was always the least injured in some fatal accident he caused.

I think you're probably under the influence of selection bias. This can
happen in many ways. For example, you hear about and remember the
injuries that happen to your friends (or your "cohort"), but you don't
hear about most of the injuries that happen to "idiots," because you
tend to avoid the idiots.

There's also another possible factor: As you've described many times,
your riding buddies are a pretty competitive bunch, and you (plural)
ride frequently in conditions that others would avoid. Even if you and
your friends have much higher skills than average, you folks may
momentarily exceed the protection of those skills by riding closer to
your limits - whether on ice, steep descents, gonzo off-road or wherever.

(In a sense, the key to avoiding crashing is keep a healthy margin
between the current hazards and your skill limits, whatever they are.
Those limits vary greatly, individual to individual; those hazards vary
greatly, moment by moment.)

In any case, I think the data's pretty solid that those with less skill
crash more often. In _Bicycle Transportation_, Forester gives data from
various sources on crash rates vs. miles ridden. Table 5-4 shows that
those who ride up to 500 miles per year have crash rates six times
higher (per mile) than those who ride 2000+ miles per year. Surely this
is because those who ride lots have developed more skills, and those
skills tend to protect from crashes.

Admittedly, there are exceptions. Other variables in the mix might be
intelligence, coordination, competitiveness, tolerance for risk, typical
riding conditions, etc.

About alcohol, there seems to be lots of data correlating drinking with
crashing. About 1/4 of fatally injured cyclists are drunk!

http://www.seattlemet.com/news-and-p...nvolve-alcohol

http://www.researchgate.net/publicat...ol_consumption

http://cityroom.blogs.nytimes.com/20...ype=blogs&_r=0



--
- Frank Krygowski