On Thu, Jan 24, 2013 at 3:49 PM, John Z Wetmore <john@pedestrians.org> wrote:

Sorry I wasn't clear in my original post --- I didn't include a quote
from the discussion that referred to injury crashes. (And sorry for
putting words in your mouth. I get tired of the religious wars over
bike lanes on some lists.) Most fatal bicycle crashes involve motor
vehicles, but most non-fatal bicycle crashes do not involve motor
vehicles. Bicycle injury crashes far outnumber fatal crashes. So
whether you are looking at total (injury plus fatal) crashes or at
just injury crashes, the majority of them do not involve motor
vehicles. Because injury crashes predominate in number, I don't
believe the order in the list changes if you include fatal crashes or not.

I also don't know how multiple causes are dealt with in the
statistics. For example, suppose there is an alluvial deposit of
gravel at the bottom of a long hill where a paved trail goes into a
turn (a very plausible scenario). A cyclist going fast down the hill
skids on the gravel when he attempts to make the turn. Do you
classify the cause as excessive speed from the hill, loose gravel, or
sharp curve?

Much planning is based on fatalities and not injuries partly because
the injury data is so spotty. If we had better injury data, it would
be easier to give weight to injury prevention when making decisions.

Thanks.

At 02:47 PM 1/24/2013, mbrenman001@comcast.net wrote:
>Guess I'm confused, John. Below, in your list, you discussed
>"crashes" and did not differentiate between injuries and fatalities.

>I did not "blame the bike-on-bike crashes on bike lanes," I said,

>"takes some of the influence away from the arguments by bicyclists

>for separate bike lanes on roads." You're right, we'd need to know
>where the injuries and fatalities occurred. This is an interesting
>question, "What weight do you put on fatalities versus severe
>injuries versus minor injuries?" and has been debated a great deal
>inside the US Dept of Transportation. They ascribe a certain dollar
>value to a death, but a severe incapacitating injury has expensive
>longterm costs for society and the individual.
>Marc
>
>

>----------
>From: "John Z Wetmore" <john@pedestrians.org>
>To: "TRB Health and Transportation" <h+t--friends@chrispy.net>

>Sent: Thursday, January 24, 2013 10:17:50 AM

>Subject: Re: [H+T--Friends] A Data Question
>
>
>First, this is injury data. Most bike fatalities are from crashes
>with cars. What weight do you put on fatalities versus severe
>injuries versus minor injuries?
>
>Second, you would need much more detailed data to determine where the
>bike-on-bike collisions are occurring. Are they in bike lanes? Are
>they on trails? Are they in regular travel lanes? Do they involve
>wrong-way cyclists, who are involved in many collisions with
>cars? Do they happen in pelotons on group rides? It would take some
>huge assumptions to use the aggregate data to blame the bike-on-bike
>crashes on bike lanes.
>
>
>
>At 11:51 AM 1/24/2013, mbrenman001@comcast.net wrote:
> >This is very interesting, John. The lack of injuries from cars takes
> >some of the influence away from the arguments by bicyclists for
> >separate bike lanes on roads. In fact, since the top cause of
> >injuries is other bicyclists, then as there are more, and closer
> >together, one would expect more injuries.
> >Marc Brenman
> >mbrenman001@comcast.net
> >
> >
> >----------
> >From: "John Z Wetmore" <john@pedestrians.org>
> >To: "TRB Health and Transportation" <h+t--friends@chrispy.net>
> >Sent: Wednesday, January 23, 2013 7:26:24 PM
> >Subject: Re: [H+T--Friends] A Data Question
> >
> >
> >The second interview on Episode 110 of "Perils for Pedestrians" on
> >bicycle engineering also gets into the causes of bike crashes. The
> >top causes, in order of importance:
> >-other bicyclists
> >-debris
> >-potholes
> >-hills
> >-turns
> >-animals
> >-inattention
> >http://www.youtube.com/watch?v=2PqYJfvwGcI
> >
> >As others have said, the majority of non-fatal bicycle crashes do not
> >involve motor vehicles. You can pick up the more serious incidents
> >with ambulance or hospital data, but a lot of bruises and road rash
> >are treated at home and would only be picked up by a survey of cyclists.
> >
> >You see a similar pattern with pedestrians. Most fatal incidents
> >involve motor vehicles, but falls result in more hospitalizations
> >among the elderly.
> >
> >John Z Wetmore
> >john@pedestrians.org
> >Producer of "Perils For Pedestrians" Television
> > www.pedestrians.org
> >--------------------------------------------------------------------

John Z Wetmore
john@pedestrians.org
Producer of "Perils For Pedestrians" Television
www.pedestrians.org
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