Little more descriptive title maybe?
One has to wonder about the biases of the data used for the Cross Fisher studies that have been the basis for Effective Cycling et. al..
I understand that the Cross studies were based on reading police reports... if these reports were heavily biased, then that could have tilted the outcome of the studies.
"I'm in shape -- round is a shape." Andy Rooney
But the data that much of his work is based upon is from studies made in the 70s gathered from police reports that were most likely biased. and as ILTB points out, the data was probably further cherry picked to meet certain hypothesis.
Meanwhile, other places have shown that cyclists can well get along well in society with a nice mix of political support and facilities, such as exist in many European cultures and even here in Portland Or. (now with a 6% model share). Yet that very reality is denied by those "schooled" in Forester's model.
So on one hand we have one concept probably fueled by biased data. On the other, we have clearly observable results. And because of this dichotomy, this vast rift exists in the cycling community.
As an example of a conclusion error; since most cycling crashes happen to sober cyclists riding on 25mph roads and hardly any crashes happen to drunk cyclists on 65+mph roads, so therefore riding drunk on the expressway must be the safest way to ride.
What we do have is a list of the relative dangers of car/bike interactions, logically we could spin off a couple of alternate universes where we would be teaching how to ride safe while riding against traffic or how to ride safe while cycling on the sidewalk. The reasons why we did not choose those routes should be self evident.
So now what is in question is the methodology employed to mitigate the dangers of car/bike interactions, which is based on our experience, observations and assumptions. In short safe cycling is based on our bias but only because nothing better is available.
Velo news even reported that there was a bias of police tending to question motorists while ignoring live cyclists... again if the motorist is seeking to cover their behind, the resulting report will tend to convey the data the motorist wants the police to believe, regardless of the truth.
One can be as objective as possible while compiling the data, but if the data is based on bias and lies, then the outcome will tend to reflect that input. (Garbage in ----> Garbage out)
I am sure the review process did verify that Cross and Fisher were objective about their methods of cataloging the data... but again, if the data were flawed...
One can also think about the bias itself and what it means for the analysis and model fitting. My guess is that drivers probably stretch the truth more than make-up fairy tales. For example, a driver would probably say that the cyclist failed to stop at the light/intersection than completely fabricate a story where the cyclist was riding on the wrong side of the street.
Anyway, this doesn't change the fact that exposure in many of these studies is unobserved ... although I have seen a reference to one that did ... such that the probabilities/rates that we would want to know are unknown.
I still don't know why, however, one would think that U.S. accident data is so terrible such that zero inferences can be made while the data about the glorious and safe cycling in Europe is unaffected. If anything, it would seem as if a European driver has a greater incentive to lie -- since they have increased liability -- after an accident than a US/British driver.
And again what would change and be the implication that all/most wrong way crashes are misclassified and should be be classified as same direction crashes. That would then assert that wrong way cycling is the safest.
In other words what specific outcome of this study that we should be highly suspicious of and how is that based on some logic of misclassification? Bias maybe but without any evidence the bias has altered the outcome we really cannot make a case that a bias has influenced the outcome.
It is sort of like accusing a person of a particular race of having a bias in hiring practices but if the ratio of race hired is where we would expect it then what is the evidence of a bias other then it "could" exist.
Almost all official stuff in regards to bicycling stinks in someway, but that does not mean we should throw it all out and not look into it in some detail to see what we can and cannot assert from it.
Are bike lanes as bad as has been suggested for instance...
What really is the frequency of overtaking collisions as another.
Perhaps cycling is not quit as safe as some portray it... and what can be done to increase said safety.
All these are issues that bear further examination... and to depend on the 30+ year old data from a study that compiled questionable data is at the very least something that we should stand up and confront.
And I guess we should be questioning the results of the "European model" with the same skeptical eye ...
Genec, As far as I am aware reports do not suggest bike lanes are bad, it is JF in particular that makes an argument based on lawful cyclists behavior bike lanes should have a slight decrease in safety. And I counter that with an argument without bike lanes we must also include unlawful cyclists (wrong way and sidewalk riding) so we should see a slight decrease in safety without bike lanes as well.
I agree we need a new study and it is something I am working locally on. But as far as getting data that would support that VC is safer then bike facilities how the heck would one determine if a cyclist is VC or not? Use JF criteria that there is only 3-4 VCs in this forum? Make all VC wear a yellow arm band so we know for sure? Use the criteria established on this forum that if a cyclists was in an accident then they were not riding in the proper VC fashion? It seems to me we are a long way off from "proving" the safety of VC.
The other problem with the 30 year data is the assertion that intersections are the most dangerous for us. According to FARS intersections account for only a 1/3 of our fatalities. There may be a reason to be afraid of same directional traffic after all.
Even more so this was the model used by HH with his claims that accidents for vehicular cyclists with the right attitude were as unlikely as being hit by a meteor. Anyone hit by a motor vehicle musta been doing something wrong!
But in the meantime, no where has any other form of cycling advocacy (or promotion or whatever you want to call it) been able to increase the numbers of cyclists. Look at Portland for instance and their insistence that they now have a mode share of some 6%... no where else in the US is anywhere near as high. One has to ask... what makes the difference.
Is it the fees and restrictions on motoring as John Forester states... Well there are no such fees and restrictions in Portland. Is it the geography of the area... matched in other places. So what is making the difference???
For example in 2005 Mesa, AZ the data on the surface would indicate 56% intersection related and 44% mid-block collisions.
Now take that 44% mid-block collision and break them down by not counting collisions where the cyclist was crossing the street mid-block (12.3%) and not counting collisions at private drives (25%), then of the total mid block collisions where the cyclist was not crossing the street and the cyclist was not crossing a private drive, then there are remaining 6.5% (1.4% wrong way) mid-block collisions and 81% private drive or intersection related.
Al, thanks for the Mesa bike crash analysis link very interesting (and very different then here.)
Now part of my argument is there is a vast difference between crashes and crashes that cause a fatality. While I do not want to end up in a hospital, it would be preferable to death. To demonstrate how fatality data does NOT follow crash data look at the age of those most represented in crashes (10-15) and those in fatalities (45-54.) No one has studied just the fatality data.
What Mesa reports as mid-block/intersection should be the same thing as what FARS reports, the ratio is different because we are talking about a subset of all crashes.
Thanks to what you provided I would speculate the main cause of cyclists deaths is these two items:
Across Roadway (J-biking?)
Sidewalk - Private Drive - Against Traffic
Both of these should be classified as mid-block crashes but a factual answer to what are the most fatal crash types is still unanswered.
Last edited by The Human Car; 04-14-08 at 08:09 PM. Reason: grammar