Advocacy & Safety - Is Bicycling Safe? (editorial in "Raise the Hammer"))

The following is an editorial from Raise the Hammer (http://www.raisethehammer.org/index.asp?id=617), a Canadian website. It was originally posted by maddmike in Living Carfree (http://bikeforums.net/showthread.php?t=342619), but I thought you all might be interested in tearing it apart, or whatever.










IS BICYCLING SAFE?


by Ryan Mcgreal


Raise the Hammer promotes cycling as a great transportation choice. It's cleaner and healthier than driving, producing zero emissions and achieving the equivalent of 595 km/l (1,400 mpg) in fuel economy.

Nevertheless, would-be cyclists often ask: But is it safe? Will I have to pay for my environmental choice with crippling injuries or premature death?

An article in View Magazine a couple of months ago advocated for better bicycle infrastructure by focusing on cycling dangers. Though well-intentioned, it reinforced many preconceptions without examining them for accuracy.

In fact, cycling is arguably safer than driving.

Comparing the Risks
Every activity carries risks, and are many possible ways to compare the relative risks of cycling and other activities. Looking at several can help to form a more complete picture.

Fatality by Distance Cycled
The most obvious comparison is the fatality risk per distanced traveled. In this straight-up analysis, cycling is more dangerous than driving. Every 1.6 million kilometres (one million kilometres) cycled produces 0.039 cyclist fatalities, compared to 0.016 fatalities for motorists. They're both very low, but the risk for cycling is more than double.

However, this is not the most useful way to compare risks.

Fatality by Time Spent Cycling
Failure Analysis Associates, Inc. performed a comparative analysis of fatality rates for a variety of activities per million hours spent performing a given activity. They concluded that the fatality rate for every million hours spent cycling is 0.26, compared to 0.47 per million driving hours (on-road motorcycling comes in at a whopping 8.80 deaths per million motorcycling hours).

That is, riding a motor vehicle has nearly twice the risk of fatality as riding a bike for a given duration.

Overall Fatality and Commute Homeostasis
According to the US National Safety Council, for every million cyclists in the US, 16.5 die each year, whereas for every million motorists, 19.9 die each year.

This is important, because it helps us to draw conclusions about how the higher risk per distance traveled interacts with the lower risk per time spent traveling. Cycling is more dangerous on a straight distance comparison, but because drivers travel farther on average, the overall risk to an individual is higher for drivers than for cyclists.

This is related to what we might call "commute homeostasis", or the amount of time a person is willing to spend traveling. All things being equal, a person is willing to travel a farther distance only if they can get there faster.

People who drive tend to live farther away from destinations (e.g. work commute) than people who cycle. In fact, one benefit of cycling is that it saves so much money that cyclists can often afford to live much closer to where they work.

Cycling also tends to place a premium on proximity, so cyclists are more likely to locate in places where many destinations are nearby, which reduces the cycling distance and hence the risk as a function of distance.

Fatality Rate in Crashes
Another way of evaluating risk is to examine the odds of dying if you do crash. Common sense dictates that crashing in a bicycle has a higher risk of death than crashing in a motor vehicle, but according to the NHTSA, bicycles compare rather well.

The odds of dying from a bicycle crash are one in 71. This compares to one in 75 for a light truck (pickup truck, SUV, van), one in 108 for a car, one in 43 for a truck, one in 26 for a motorcycle, and one in 15 for a pedestrian.

In other words, the odds of dying in a bike crash are about the same as the odds of dying in an SUV crash. The false sense of security that comes from an SUV tends to produce far more dangerous driving behaviour.

Collision From Behind

Possibly the most feared collision among would-by cyclists is the collision from behind by a fast-moving car. This only makes sense: it's frightening because it seems unavoidable, because the novice cyclist feels powerless against a two-tonne projectile passing too closely.

However, such collisions make up only a small percentage of total bicycle crashes. According to a 2003 study in Toronto, collisions involving a motorist overtaking a bicycle accounted for only 11.9 percent of the total. Among those collisions, the cyclist contained minimal or minor injuries in nearly 90 percent of the incidents.

Ken Kifer provides some excellent advice on how to maximize your safety around passing vehicles.

"Life Years" Gained and Lost

In addition to the direct risk of death or injury, cycling and driving also carry indirect risks that must be factored into account.

According to a study by the British Medical Association, the average gain in "life years" through improved fitness from cycling exceeds the average loss in "life years" through cycling fatalities by a factor of 20 to 1.

Driving confers no commensurate health benefits through improved fitness; in fact, time spent driving actually correlates with poorer overall health and higher risk of heart disease, obesity, diabetes, cancer, and related lifestyle diseases.

Psychologically, it's hard to weigh the slight risk of being hit by a car tomorrow against the vastly reduced risk of having a heart attack in twenty years, but it is far too significant to ignore.

Risk is Mutable

Since cyclists are not a homogeneous bunch, it makes sense to examine whether and how cycling behaviour affects fatality rates. It turns out that cyclists who ignore the rules are much more likely to die than cyclists who follow the rules.

The difference is so stark that it would make more sense to regard them as two separate populations for the sake of comparison. Averaging the two groups - cyclists who follow or who disregard the law - together obscures the vast differences in their relative risks.

It also obscures the fact that an individual cyclist's choices strongly influence their risk of fatality. Cyclists are not helpless victims of safety statistics (even encouraging statistics).

It might not be politically expedient to state, but in the majority of bicycle crashes, the cyclist is at least partly at fault. Cyclists are hit when they ride on the sidewalk and appear out of nowhere at intersections; when they pass on the right; when they ride at night without lights and reflectors; when they ride the wrong way down one way streets; when they ride too closly to parked cars; and so on.

Bike infrastructure can certainly help: streets with clearly marked, well-maintained bike lanes are safer than streets without them. It's also clear that bike lanes increase the perception of safety for would-be cyclists.

However, the way you ride is a bigger factor in accident prevention. The absolute best way to avoid accidents is to ride as though you are driving a motor vehicle. In other words: be visible, follow the rules of the road, pay close attention to what's happening around you, and practice defensive riding. You will earn the respect of motorists, maximize your safety, and get the most enjoyment from cycling.

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Ryan lives in Hamilton with his family and works as an analyst, web application developer, writer, and journal editor. He is the editor of Raise the Hammer. Ryan also writes occasionally for CanadianContent.Net, and maintains a personal website.




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How old is this article? Ken Kiefer was killed by a drunk driver four years ago.

Also, I guess you can prove anything if you swing the statistics your way.

I think the last paragraph sums it up:

However, the way you ride is a bigger factor in accident prevention. The absolute best way to avoid accidents is to ride as though you are driving a motor vehicle. In other words: be visible, follow the rules of the road, pay close attention to what's happening around you, and practice defensive riding. You will earn the respect of motorists, maximize your safety, and get the most enjoyment from cycling.

Good article. I think it's good that he compares different statistics that go different ways. I think he's right that "looking at several can help to form a more complete picture", and it's a more credible way of using statistics than only selecting the ones you like. It also brings together a bunch of different studies and conclusions that have been discussed separately on this forum.

And if you go to the original link, he includes a very funny but very relevant Calvin & Hobbes comic!

http://www.raisethehammer.org/images/calvin_hobbes_look_down_the_road.gif

There are some good stats in here. I'm doing a safety training presentation next month at work on cycling safety. I'll be using this info.

The following is an editorial from Raise the Hammer, a Canadian website. It was originally posted by maddmike in but I thought you all might be interested in tearing it apart, or whatever.

Or whatever – Briefly:
First, the essay repeats the simple minded conclusions made by of others about comparative risk of grossly generalized/homogenized populations of cyclists, with grossly generalized/homogenized populations of motorists. The same fatal flaw applies to the homogenizing of all cycling activities as if they presented equal risk. It is foolish to draw conclusions about cycling risk by combining (or comparing) the accident records of populations of 8 year olds cycling to school on weekday mornings, teenage boys cycling anywhere, convicted DUIs cycling to work (or the liquor store) during rush hour, club rider pelotons cruising suburban roads on Sunday morning, and numerous other diverse cycling populations, locations, and activities. The same foolish notion applies to the idea of considering all motorist populations, motoring locations, and motoring activities to be identical in risk.

Secondly, at the conclusion of the article, the writer notes that cyclists are not a homogenous group and makes numerous unsubstantiated statements of opinion about various writer favored behaviors being much safer with no references at all.


A few more notes about the first two "studies" in the article:
The first obvious question is where did the "analysts" come up with meaningful metrics about cycling mileage or hours? I presume a crystal ball. Did the studies include automobile passenger metrics too? Did it increase the mileage/hours totals for cars with passengers? Did they include their fatalities?
Also risk free cycling/motoring is not strictly determined by freedom from fatal accidents. Accident severity must be considered but an all or nothing measurement of fatalities is not sufficient. If it can be shown that minor/serious/catastrophic injuries injuries/mile tracks with fatalities/mile then there might be something here worth discussing.


Overall Fatality and Commute Homeostasis
According to the US National Safety Council, for every million cyclists in the US, 16.5 die each year, whereas for every million motorists, 19.9 die each year.
A ridiculously simplified generalization (and worthless statistic)that assumes all cyclists are identical as well as that all motorists are uniform in their motoring activity


In fact, one benefit of cycling is that it saves so much money that cyclists can often afford to live much closer to where they work."
References?


Cycling also tends to place a premium on proximity, so cyclists are more likely to locate in places where many destinations are nearby, which reduces the cycling distance and hence the risk as a function of distance.
References? IMO the writer has cause and effect backwards. Really, how many people (outside of a relative handful of car free aficionados) make important decisions about employment, residence, and lifestyle primarily based on their cycling preferences?


Fatality Rate in Crashes
Another way of evaluating risk is to examine the odds of dying if you do crash. Common sense dictates that crashing in a bicycle has a higher risk of death than crashing in a motor vehicle, but according to the NHTSA, bicycles compare rather well.

The odds of dying from a bicycle crash are one in 71. This compares to one in 75 for a light truck (pickup truck, SUV, van), one in 108 for a car, one in 43 for a truck, one in 26 for a motorcycle, and one in 15 for a pedestrian.

In other words, the odds of dying in a bike crash are about the same as the odds of dying in an SUV crash. The false sense of security that comes from an SUV tends to produce far more dangerous driving behavior.
This study cherry picks the data to confuse the reader. Pumping up the number of bike accidents by using meaninglessly vague terms such as bicycle "crashes". Every so-called "risk study" I have ever seen that used the vague term "bicycle crashes" or "crash rate" inflates the numbers with insignificant "falls" that involved no other vehicle. More useful conclusions could be made by comparing apples with apples.


Collision From Behind
Possibly the most feared collision among would-by cyclists is the collision from behind by a fast-moving car. This only makes sense: it's frightening because it seems unavoidable, because the novice cyclist feels powerless against a two-tonne projectile passing too closely.

However, such collisions make up only a small percentage of total bicycle crashes. According to a 2003 study in Toronto, collisions involving a motorist overtaking a bicycle accounted for only 11.9 percent of the total. Among those collisions, the cyclist contained minimal or minor injuries in nearly 90 percent of the incidents.

You sure this so-called "analysis" wasn't ghost written by John Forester? "Crashes" and collisions again are combined wily nily. For this study the fatality and injury rate comparisons are ignored; just the total number of accidents regardless of severity.

The rest of the article below is just so much unsubstantiated editorializing and assumption making about cycling behavior and risk by the writer. Its value/validity is as good as its references.


Since cyclists are not a homogeneous bunch, it makes sense to examine whether and how cycling behavior affects fatality rates. It turns out that cyclists who ignore the rules are much more likely to die than cyclists who follow the rules.

The difference is so stark that it would make more sense to regard them as two separate populations for the sake of comparison. Averaging the two groups - cyclists who follow or who disregard the law - together obscures the vast differences in their relative risks.

It also obscures the fact that an individual cyclist's choices strongly influence their risk of fatality. Cyclists are not helpless victims of safety statistics (even encouraging statistics).

It might not be politically expedient to state, but in the majority of bicycle crashes, the cyclist is at least partly at fault. Cyclists are hit when they ride on the sidewalk and appear out of nowhere at intersections; when they pass on the right; when they ride at night without lights and reflectors; when they ride the wrong way down one way streets; when they ride too closely to parked cars; and so on.

Bike infrastructure can certainly help: streets with clearly marked, well-maintained bike lanes are safer than streets without them. It's also clear that bike lanes increase the perception of safety for would-be cyclists.

However, the way you ride is a bigger factor in accident prevention. The absolute best way to avoid accidents is to ride as though you are driving a motor vehicle. In other words: be visible, follow the rules of the road, pay close attention to what's happening around you, and practice defensive riding. You will earn the respect of motorists, maximize your safety, and get the most enjoyment from cycling.

Well I liked it. And I do feel safer on my bike than in my car in most situations.

ILTB makes some good points regarding the context of the statistics and their interpretation. I will add that the selection biases in who cycles/drives, for what purposes, and when they drive/cycle influences the rough statistics and their meaning. For instance, suppose many people will not cycle in the rain or during evening hours but will drive during those same circumstances. Clearly, assuming that we all agree that cycling/driving in dark or wet conditions is more dangerous, the population statistics would fail to capture the relative risks of the two activities.

-G

The following is an editorial from Raise the Hammer (http://www.raisethehammer.org/index.asp?id=617), a Canadian website. It was originally posted by maddmike in Living Carfree (http://bikeforums.net/showthread.php?t=342619), but I thought you all might be interested in tearing it apart, or whatever.

[...]

... It turns out that cyclists who ignore the rules are much more likely to die than cyclists who follow the rules.

The difference is so stark that it would make more sense to regard them as two separate populations for the sake of comparison. Averaging the two groups - cyclists who follow or who disregard the law - together obscures the vast differences in their relative risks.[...]

I'm not sure if the author is just confused or deliberately trying to mislead, but there are some common and important misconceptions here that deserve correction.

Of the 15-20% of cyclist-involved crack-ups that involve collision with a motor vehicle -- the collisions which produce the vast majority of cyclist deaths -- the cyclist is deemed to be 'at fault' (in the strict legal sense) about half the time, maybe a bit more than half the time. But this is only true if we look at the entire population of cyclists, including children, teenagers and rank beginners. If we look only at car-bike collisions involving adult riders, the cyclist was following the law and not 'at fault' in the majority of instances.

Those of us who spew safety tips for cyclists need to move well past the fairy-tale that simply following the rules will make everything okay.

Robert

Or whatever – Briefly:
First, the essay repeats the simple minded conclusions made by of others about comparative risk of grossly generalized/homogenized populations of cyclists, with grossly generalized/homogenized populations of motorists. The same fatal flaw applies to the homogenizing of all cycling activities as if they presented equal risk. It is foolish to draw conclusions about cycling risk by combining (or comparing) the accident records of populations of 8 year olds cycling to school on weekday mornings, teenage boys cycling anywhere, convicted DUIs cycling to work (or the liquor store) during rush hour, club rider pelotons cruising suburban roads on Sunday morning, and numerous other diverse cycling populations, locations, and activities. The same foolish notion applies to the idea of considering all motorist populations, motoring locations, and motoring activities to be identical in risk.

Secondly, at the conclusion of the article, the writer notes that cyclists are not a homogenous group and makes numerous unsubstantiated statements of opinion about various writer favored behaviors being much safer with no references at all.


A few more notes about the first two "studies" in the article:
The first obvious question is where did the "analysts" come up with meaningful metrics about cycling mileage or hours? I presume a crystal ball. Did the studies include automobile passenger metrics too? Did it increase the mileage/hours totals for cars with passengers? Did they include their fatalities?
Also risk free cycling/motoring is not strictly determined by freedom from fatal accidents. Accident severity must be considered but an all or nothing measurement of fatalities is not sufficient. If it can be shown that minor/serious/catastrophic injuries injuries/mile tracks with fatalities/mile then there might be something here worth discussing.


A ridiculously simplified generalization (and worthless statistic)that assumes all cyclists are identical as well as that all motorists are uniform in their motoring activity


References?


References? IMO the writer has cause and effect backwards. Really, how many people (outside of a relative handful of car free aficionados) make important decisions about employment, residence, and lifestyle primarily based on their cycling preferences?


This study cherry picks the data to confuse the reader. Pumping up the number of bike accidents by using meaninglessly vague terms such as bicycle "crashes". Every so-called "risk study" I have ever seen that used the vague term "bicycle crashes" or "crash rate" inflates the numbers with insignificant "falls" that involved no other vehicle. More useful conclusions could be made by comparing apples with apples.



You sure this so-called "analysis" wasn't ghost written by John Forester? "Crashes" and collisions again are combined wily nily. For this study the fatality and injury rate comparisons are ignored; just the total number of accidents regardless of severity.

The rest of the article below is just so much unsubstantiated editorializing and assumption making about cycling behavior and risk by the writer. Its value/validity is as good as its references.

Thanks for taking the time to respond to this. I'm wondering if there are any conclusions about cycling safety that are warranted by the data that's available? Or is the data so poor that it's best not to make any conclusilons?

I'm not sure if the author is just confused or deliberately trying to mislead, but there are some common and important misconceptions here that deserve correction.

Of the 15-20% of cyclist-involved crack-ups that involve collision with a motor vehicle -- the collisions which produce the vast majority of cyclist deaths -- the cyclist is deemed to be 'at fault' (in the strict legal sense) about half the time, maybe a bit more than half the time. But this is only true if we look at the entire population of cyclists, including children, teenagers and rank beginners. If we look only at car-bike collisions involving adult riders, the cyclist was following the law and not 'at fault' in the majority of instances.

Those of us who spew safety tips for cyclists need to move well past the fairy-tale that simply following the rules will make everything okay.

Robert

Thanks for the response. I wonder are you concluding that it's less risky for a rider to ignore the laws? If so, how can it be determined which laws should be ignored by the cyclist? Should the laws (vehicle code) be changed to make cycling safer?

Thanks for taking the time to respond to this. I'm wondering if there are any conclusions about cycling safety that are warranted by the data that's available? Or is the data so poor that it's best not to make any conclusilons?

There is some data available that indicates certain safety trends (or lack of such) if not logical conclusions, however the article in your OP does not reference any of them and just cherry picks a few snippets to fill gaps in his screed.

I think many advocates, and especially safety nanny types, are impervious to logical conclusions if not in agreement with their own agenda, hence their reliance on voodoo/pseudo data to draw the proper conclusions.

Possibly the most feared collision among would-by cyclists is the collision from behind by a fast-moving car. This only makes sense: it's frightening because it seems unavoidable, because the novice cyclist feels powerless against a two-tonne projectile passing too closely.

However, such collisions make up only a small percentage of total bicycle crashes. According to a 2003 study in Toronto, collisions involving a motorist overtaking a bicycle accounted for only 11.9 percent of the total. Among those collisions, the cyclist contained minimal or minor injuries in nearly 90 percent of the incidents.

Another clinic on how to lie with statistics.

That was 11.9% of all cyclist collisions, including all of those (around 30%) where the rider was on the sidewalk, and hence ineligible for this type of collision.

Let me put my own read on the same study:

That Toronto study found that overtaking accidents caused 40% of all the cycling fatalities in the study, and more than half of fatalities where the cause of the accident could be classified.

Or, based on the way the study approximated fault, 80% of fatalities when the cyclist was not at fault were motorist-overtaking.

Of course, this study also suggested that five out of eight cyclists in classifiable fatal accidents were killed by at-fault motorists. The article fails to mention anything about the fatalities in this study, and then goes on about how cyclists who ignore the rules are a totally different risk class.

And he then makes unsupported theories about things like wrong-way riding, which the Toronto study put as a cause of a whopping 2.5% of all accidents.

http://www.toronto.ca/transportation/publications/bicycle_motor-vehicle/

Another clinic on how to lie with statistics.

That was 11.9% of all cyclist collisions, including all of those (around 30%) where the rider was on the sidewalk, and hence ineligible for this type of collision.



So that makes it really 17%.

And he then makes unsupported theories about things like wrong-way riding, which the Toronto study put as a cause of a whopping 2.5% of all accidents.

http://www.toronto.ca/transportation/publications/bicycle_motor-vehicle/


My favorite part of the Toronto study is this paragraph from the conclusion:


By identifying the most frequent types of collisions, and those that tend to lead to more serious injuries, the findings of this study can help police develop more effective traffic enforcement campaigns. For
example, while there may be a perception that many cyclists recklessly disobey stop-signs and traffic signals, our analysis shows that less than 3% of collisions involve a cyclist failing to stop at a controlled intersection. Targeted stop-sign enforcement campaigns along busy cycling routes may result in large numbers of tickets being issued, but their effectiveness in improving traffic safety is questionable. Enforcement that focuses on driving and cycling infractions that are found to contribute most often to collisions and injuries can be expected to yield better results, in terms of improving safety, than campaigns that simply target infractions that are easy to enforce.

So while everyone loves to rail against wrong-way cyclists and those who ignore stop signs and red lights, the statistics show they're not such a big deal.

One issue with the Toronto study is that it has a very broad definition of overtaking accidents, any time that a bike and car are going in the same direction and collide. This conflates three very different types of collisions: driver rear-ends cyclist; driver mis-judges passing distance; and cyclist swerves into path of overtaking car.

Thanks for the response. I wonder are you concluding that it's less risky for a rider to ignore the laws? If so, how can it be determined which laws should be ignored by the cyclist? Should the laws (vehicle code) be changed to make cycling safer?

I am not concluding that it's less risky to ignore laws. I can only conclude, however, with the limited stats available and my own experience and observation, that the degree to which one follows traffic law is not the critical factor determining one's likelihood of being hit by a car.

The critical factor, I believe, is that state-of-mind which goes by various names but which I have called 'situational awareness' as well as 'vigilance.' Ultimately, I believe that the safest rider is probably the one who is both vigilant and lawful. It is fair to ask an interesting question, however, a question which may produce some uncomfortable answers, especially for those who believe as I do that vigilance is more important than lawfulness: is it easier to remain vigilant while riding un-lawfully? The available statistics don't exactly contradict such a notion; my exerience as a long-time messenger strongly supports it. A veteran messenger may ride through half a million red lights in a career without incident, and, in my observation over many years, is far more likely to get hit under a green light than a red one. Make of it what you will.

Robert

It is fair to ask an interesting question, however, a question which may produce some uncomfortable answers, especially for those who believe as I do that vigilance is more important than lawfulness: is it easier to remain vigilant while riding un-lawfully?



This is a very interesting point. Sidewalks have a dismal safety record, and there is no strong evidence that bike lanes or bike paths do anything to improve cyclist safety. I would buy the premise that being separated from traffic lowers your vigilance, to the point that it more than compensates for any benefit from a separated facility. It certainly squares with my observations of cyclists.

There is some data available that indicates certain safety trends (or lack of such) if not logical conclusions, however the article in your OP does not reference any of them and just cherry picks a few snippets to fill gaps in his screed.

I think many advocates, and especially safety nanny types, are impervious to logical conclusions if not in agreement with their own agenda, hence their reliance on voodoo/pseudo data to draw the proper conclusions.

As opposed to the no-helmet crowd, whose use of statistics is so poor as to imagine that they're already suffering from head injuries.

I would buy the premise that being separated from traffic lowers your vigilance, to the point that it more than compensates for any benefit from a separated facility.

emphasis mine ...

That is an interesting point. I did not consider that aspect of it. I guess it applies to other bike facilities as well.

As opposed to the no-helmet crowd, whose use of statistics is so poor as to imagine that they're already suffering from head injuries.

Actually I was thinking of the opposite crowd (i.e. you and your ilk) whose foamed wrapped skulls are impervious to the hard fact that emotional anectdotes and newspaper snippets are not data, analysis and/or logical arguments "supporting" a credible record of risk reduction for the population of bicycle helmet users.

emphasis mine ...

That is an interesting point. I did not consider that aspect of it. I guess it applies to other bike facilities as well.

Emphasis you forgot is that this "interesting point" is based on an unsubstantiated/undefined premise about risk: "Sidewalks have a dismal safety record."

Emphasis you forgot is that this "interesting point" is based on an unsubstantiated/undefined premise: "Sidewalks have a dismal safety record."

I did not forget anything. Those are two different ideas. I emphasized that notion that people's perceptions of risk change their behavior and the observed result obscuring the true marginal effect; e.g., we build safer automobiles and people drive more dangerously.

But feel free to talk about what "we know"/"think we know"/"are clueless" about sidewalk riding.

I did not forget anything. Those are two different ideas. I emphasized that notion that people's perceptions of risk change their behavior and the observed result obscuring the true marginal effect; e.g., we build safer automobiles and people drive more dangerously.

But feel free to talk about what "we know"/"think we know"/"are clueless" about sidewalk riding.

"thinks he knows" fits the premise DC Commuter made about the "dismal safety record" of sidewalk cycling.

"thinks he knows" fits the premise DC Commuter made about the "dismal safety record" of sidewalk cycling.

Taking the statement on its own without any prior knowledge, it would be misleading.

My concluion from the discussion so far is that there's not enough valid data to support any logical conclusions about cycling safety, so we as cyclists are still at the point of "Whatever seems safe is safe...unless it isn't."

My concluion from the discussion so far is that there's not enough valid data to support any logical conclusions about cycling safety, so we as cyclists are still at the point of "Whatever seems safe is safe...unless it isn't."

A logical conclusion drawn from the current available data given the state of its validity/credibility/sources. I'd rephrase your conclusion as "whatever seems like acceptable risk is acceptable until it no longer seems acceptable as circumstances/cycling environment change."

My concluion from the discussion so far is that there's not enough valid data to support any logical conclusions about cycling safety, so we as cyclists are still at the point of "Whatever seems safe is safe...unless it isn't."

Well ... I think that you have to be Bayesian about the process. In other words, one needs to think of a justifiable set of priors about the world, apply a reasonable model, and see whether the data supports or rejects the model and priors. Complete data that can answer some of the detailed questions discussed in this forum--particularly in a Frequentist world--is unlikely to come about anytime soon. Hence, my conjecture that a more sophisticated analysis is needed overcome certain issues where we can directly quantify the amount of uncertainty given a "true" model (i.e., relationships between the parameters) and the data. However, I think that it is important to be clear about what assumptions one makes when stating conclusions.

What I describe above is what I believe most people do in their head. We look at the descriptive statistics. We interpret them a particular way given our priors about how the way the world works ... in this case regarding the world of cycling. An explicit model, however, would make the assumptions clear--although not necessarily its effects--for others to evaluate and change.

For instance, if one really believes that wrong-way riding is "safe" or safer than riding with traffic, I think that one should try to seriously consider what assumptions they are making about the world and figure out whether their mental model is a good one given the rough statistics observed.