Monday, November 21

Close Calls Concern

In a lot of blogs concerning bicycles, I hear about "scary" stuff such as close calls and aggressive motorists. Sometimes these stories are sincere and sometimes they are just that - stories. However, close calls relate to a real safety concern. Namely, the "safety pyramid." Close calls that are invented as a means to scare people are a different kind of problem, and that'll be the subject of a future post.
The Safety Pyramid. How Many Stop Signs Can You Run Before a Close Call?
How Many Close Calls Before You Get Hit? And So On...
The "safety pyramid" relates to an industrial observation that bad events (in this case, cycling crashes and collisions) are related to the numbers of less serious close calls. The traditional relationship is as shown in the picture below.
In the case of cycling, "at risk behaviors" would consist of things like riding on sidewalks, riding without lights, running stop signs and other behaviors that any reader of this blog would know. The theory behind the safety pyramid suggests that you can cut down the number of near misses and worse simply by cutting down risky behaviors. Exactly the same principle works if you're driving a car.
Does this work? Well, perhaps it does and perhaps it doesn't. Certainly you cannot reduce your risk in traffic to zero by any reasonable action. A motorist can (and they DO) come crashing into your house and kill you as you sleep in your bed. However, I personally think that reducing "at risk" behaviors does reduce near misses. The last time I had a near miss with a motorist was in 1973. I did have a couple of close passes a couple of years ago, but they were on a really substandard road, noted here.
In reality, this is what one would expect with a normal distribution of motorist responses to a cyclist action. Six Sigma in the real world!
IF YOU seem to be having an unusual number of close calls or other safety-related encounters, perhaps it is time to reconsider. Motorists are TRAINED not to run into things and, mostly, they do not do so, or the carnage on the highways would be even greater than it is nowadays.
Speaking of which, at least ONE Law Enforcement Agency, the Ohio State Patrol, thinks the same way as I do...
Ohio Highway Patrol View on the Safety Pyramid

8 comments:

Steve A said...

I suppose THIS post is somewhat subversive as well!

Khal said...

Good post, Steve. We teach pretty much the same stuff here.

John Romeo Alpha said...

Came here for a memorable Steve A quote. Found "a normal distribution of motorist responses to a cyclist action. Six Sigma in the real world!" Leaving satisfied. Awareness, fast reaction time, and flawless avoidance technique have saved my bacon from destruction by another driver at least twice while driving a car.

RANTWICK said...

Yep. Agreed. What's Six Sigma?

limom said...

I like the pyramid.
Makes sense.

Chandra said...

Talking Gaussian, eh? Cool!
Paz :)

Steve A said...

Rantwick - for the short answer, go here.
http://dfwptp.blogspot.com/2010/03/five-whys-for-cateye.html

I'll do a special "Six Sigma" post before long.

cafiend said...

The uncontrollable variable is the risk-taking behavior of other road users, be they motorists or inconsiderate bike riders (Not to call them cyclists) who DO engage in acts like sidewalk riding, stop sign running and the like. Taking the lane can force overtaking motorists to consider their actions and it does put you in a better position to respond to a left cross. Still, bicyclists are the most vulnerable wheeled user group. This leads the the perception of risk much greater than the actual risk, because the collisions result in such unequal damage.

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