meanwhile

Another reason the study seems to be junk: a lot of hits at intersections can be classified as "behinds" but they are NOT what most cyclists think of as overtaking hits. (And most serious accidents happen at junctions https://www.bicyclinglife.com/Library/riskfactors.htm)

wphamilton

"No surprise" comes from prior knowledge

Can you stop pestering my posts please? I've already told you that you're in my filter.

I-Like-To-Bike

The study you cite gathered NO data on the severity of injuries suffered as a result of reported accidents, they just totaled up all accidents as if they all were equal. As a result no credible conclusion about cycling risk can be made from such careless methodology.

How did you arrive at at using the term serious accidents? Do you consider any reported accident as serious? Even the authors of the report never described any of the accidents as "serious." With their bogus methodology all accidents produce equal results and are considered equal for risk analysis purposes.

CommuteCommando

A lot of talk and argument over the validity of this statistic over that. For me it comes down to this. It is not disputed that flying on a commercial airline is safer than driving. I doubt that anyone will dispute that driving is safer than cycling. The first fact does not, and IMO, should not dissuade people from driving any more than I will let the second dissuade me from cycling.

dougmc

Quite a few people have disputed that.

Ken Kifer did, for example, writing an entire page where he did some impressive statistical cherry picking to show that cycling was indeed safer than driving. And then, alas, he got killed by a drunk driver.

But it gets worse. It's easier to look at deaths, because good data is available on that, but if you attempt to include injuries it becomes harder to come up with good data, but from what I can see cyclists get injured way more than motorists -- ten times as often wouldn't surprise me, but I don't have data to support that because nobody tracks it.

As far as the safety of cycling, I do believe that the fatalities are disproportionately children and other inexperienced cyclists, so if you're experienced (and know where and how to ride) and take the appropriate precautions (such as lights at night), it would not surprise me if the risk of dying becomes less per mile than that of average drivers (though maybe not experienced drivers? those teenagers are awful!) though the risk of injury is probably still significantly higher.

Either way, the risk shouldn't be high enough to keep you off your bike if you like it.

CommuteCommando

One problem with citing things like that is that it is necessary to preface it with "lets assume for the sake of argument. . ." The the record show that my statement carries that caveat.

I saw a presentation by LAB that cited Salmoning being a huge factor in bike/car collisions. (This was based on LEO reportable incidents)

njkayaker

Too many people are drawing "certain" conclusions from data that is too poor, sparce, and ambiguous to do so.

No one really knows whether it's safer or not.

It seems to me (based on "back of the envelope" calculations) that the risk of dying is about the same (smaller than a factor of ten) on a per-hour basis.

Keep in mind that there are often simple ways of increasing or decreasing your risk "significantly".

"Incidents per mile" is probably a bad way to generally compare cycling and driving.

Because the data is poor and sparse, different subpopulations are lumped together (into "all cyclists", for example). There could be very large differences in risk between subpopulations (night riders with lights and night riders without lights).

It's not valid to assume that the risk for the total population necessarily applies to individuals or subpopulations.

I-Like-To-Bike

Too true, but not a new phenomena. At least 40 years of drawing "certain" conclusions from poor, sparse and ambiguous data as well as manipulation, cherry-picking, and juggling of that same data has been used by some self proclaimed bicycle safety experts to arrive at a desired/preferred conclusion, to include the so-called conclusion that cyclists have an irrational fear of come from behind collisions.

jputnam

Depends on your definition of "safer" -- are you more concerned with *when* you die, or *how*?

Bicyclists have higher accident mortality than motorists, though not dramatically higher. So if you only care about *how* you die, and find accidents particularly horrifying, driving is safer than cycling.

On the other hand, bicyclists have significantly lower *all-cause* premature mortality -- driving increases your risk of heart disease, deep-vein thrombosis, and various cancers, while bicycling reduces coronary artery disease, diabetes, osteoporosis, and various cancers. So if you care about whether you die prematurely, regardless of what the cause of death is, driving is clearly more hazardous than cycling.

The exact magnitude of cycling's safety advantage varies based on road safety, of course. Low estimates tend to be around 10-to-1 in favor of the mortality benefits of cycling, high estimates are 20-to-1 or better. In the Copenhagen Heart Studies, for one example, it works out to 40% lower all-cause premature mortality for bicyclists -- if you could sell that in a pill, you'd make billions.

I-Like-To-Bike

Can you cite the references that bicycling is a miracle cure/snake oil for reduction of all the ailments that you claim? BTW how much bicycling does a person have to do daily and for how long a period of time to receive these health benefits?

Perhaps the next claim will be about bicycling curing bad breath, dandruff, and embarrassing naval lint?

jputnam

At this point, after decades of peer-reviewed public health research on the issue, none of those claims is at all controversial.

Most studies find dramatic reduction in coronary artery disease requires no more than 20-25 miles/week of riding, e.g., Exercise in leisure time: coronary attack and death rates. -- Morris et al. 63 (6): 325 -- Heart or Intensity versus duration of cycling, imp... [Eur J Prev Cardiol. 2012] - PubMed - NCBI The latter is especially interesting in that it evaluates cycling *intensity* vs. *duration*, finding that "the relative intensity, and not the duration of cycling, is of more importance in relation to all-cause and coronary heart disease mortality. Thus our general recommendations to all adults would be that brisk cycling is preferable to slow."

One of the most widely-cited studies followed more than 30,000 participants over more than a decade, finding, among other things, that "Bicycling to work decreased risk of mortality in approximately 40% after multivariate adjustment, including leisure time physical activity." In other words, the mortality benefit of bicycle commuting remains even when you adjust for other sports participation. (Andersen et al, All-cause mortality associated with physical activity during leisure time, work, sports, and cycling to work. All-cause mortality associated with physical... [Arch Intern Med. 2000] - PubMed - NCBI )

Some of the reduction in premature mortality may be as simple as reducing time spent sitting, Total sitting time and risk of myo... [Int J Behav Nutr Phys Act. 2014] - PubMed - NCBI

de Hartog et al attempt to express the benefits in terms of life gained or lost due to the shift from driving to bicycling, "We have expressed mortality impacts in life-years gained or lost, using life table calculations. For individuals who shift from car to bicycle, we estimated that beneficial effects of increased physical activity are substantially larger (3-14 months gained) than the potential mortality effect of increased inhaled air pollution doses (0.8-40 days lost) and the increase in traffic accidents (5-9 days lost)."

Most recently, an interesting finding from Edwards and Mason, Spinning the wheels and rolling the dice: life-cycle risks and benefits of bicycle commuting in the U.S., Spinning the wheels and rolling the dice: life-cycl... [Prev Med. 2014] - PubMed - NCBI -- "The lifetime health benefits of bicycle commuting appear to outweigh the risks in the U.S., but individuals who sufficiently discount or disbelieve the health benefits may delay or avoid bicycling. Bicycling in middle age avoids much fatality risk while capturing health benefits. Significant cross-state variations in bicycling mortality suggest that improvements in the built environment might spur changes in transit mode."

jputnam

Diabetes:

Active transportation and cardiovascular disea... [Am J Prev Med. 2012] - PubMed - NCBI "High active transportation was associated with 31% lower odds of diabetes (AOR=0.69, 95% CI=0.54, 0.88)."

Active travel to work and cardiovascular risk ... [Am J Prev Med. 2013] - PubMed - NCBI "Walking or cycling was associated with a lower likelihood of having diabetes, and walking was associated with a lower likelihood of having hypertension than private transport (AOR=0.83, 95% CI=0.71, 0.97)."

Associations between active travel to work and over... [PLoS Med. 2013] - PubMed - NCBI (Note that's from India, these issues are being investigated world-wide because of their huge public health implications.)

Bicycling to school improves the cardiometabolic ri... [BMJ Open. 2012] - PubMed - NCBI

wphamilton

I struggle with that one, because in a lot of ways incidents per mile can be better than per hour. For recreational riding, training, and racing it makes more sense to consider the time spent in the activity. But for just getting places, particularly commuting, the exposure to risk scales with distance. In typically urban and suburban settings, the environment is heavier speed traffic. More intersections and driveways, less choice in route, rush hour speeds (lower speeds). Your risks increase every time you approach and enter an intersection. Even those commuters who habitually hop onto sidewalks (too many IMO) still see the spikes in risk at driveways and cross-streets, probably an enhanced risk. So the risk there scales with miles.

It seems to me that other cycling risks are reduced for the commuter compared to the road trainer or recreational rider, and those are the risks that scale more appropriately with time than with miles. Particularly overtaking accidents, more frequent on the long rural roads, and with falls resulting from loss of control or lapses in judgment.

It does break down with night riding, where some commuters neglect lights and are at risk in proportion to the time spent on the road. But even with the flaws, I suspect that if you could find accurate data on commuters and commuting miles, and accidents while commuting (which I've yet to see), that a comparison with driving based on risk per mile would be the most meaningful.

JoeyBike

I don't have cold hard numbers associated with my research. But I do have 40 years of experience cycling in a miserable city with narrow streets and 50% intoxication level of motorists even BEFORE cell phones were invented. I also have roughly 50,000 miles of long distance touring under my belt which includes gigantic east and west coast cities as well as too many miles of twisting, blind corner roads in Appalachia, long boring stretches across the American Midwest, and the Pacific Coast Highway from end to end with high speed traffic and lots of chances to get creamed along the route by motorists gawking at the scenery.

Here is my take on the topic of rear-end collisions:

Every possible traffic scenario that you can imagine that a cyclist will encounter on public roads and highways finds the cyclist in COMPLETE CONTROL of the situation EXCEPT cars overtaking from behind or cars that have very recently overtaken the cyclist. I have never seen one single intersection that I could not cross with 100% certainty of my safety. That may mean waiting until midnight to proceed at a time when there is zero crossing traffic, but nonetheless, I am in COMPLETE CONTROL of how I cross that intersection. Only a meteor has a chance of taking me out if I do it correctly. Even a hit-man would have a hard time taking me out at a crossing UNLESS...he was coming up behind me.

Motor vehicles overtaking a cyclist is a sketchy proposition that demands a ton of trust from the cyclist being overtaken. I have ZERO trust, therefore I adjust my riding style in the city to virtually eliminate overtaking traffic (run red lights, ride the gaps created by red lights, ride it like I stole it from Tony Soprano). Or I use back streets with so many stop signs that cars have no chance overtaking me if I keep my speed up.

On the open road, the same holds true - the only risk other than falling rocks is the car or log truck overtaking me at precisely the wrong moment. So I use a rear view mirror AND my ears in an attempt to allow me a second or two to get the Hell out of the way if everything goes south all at once. Sure someone can cross the center line asleep at the wheel. I have never seen it personally although I have seen numerous oncoming vehicles decide to pass a line of cars against traffic - ME - in the opposing lane. Always a blast when it's two 18-wheelers passing each other on a narrow 2-lane road. But I can SEE THAT COMING and do something about it - like launch into the ditch. No one is generally going to pass another vehicle on a 2-lane, winding, country road and live very long but dozens or maybe even hundreds of motorists will be coming up behind me at breakneck speed every day - with enough time to react if we are all lucky.

A lot of things in this world and this life are based on reason, experience, conjecture, and basically putting 2 and 2 together. It seems to me that a situation that is totally out of the hands of a cyclist would be more dangerous (all things being equal) than situations where a cyclist can pick and choose how much risk they are willing to take. And the abject denial around here that being overtaken by a motor vehicle, especially in this world of instant communications, just astounds me. I have not had one single incident in my entire cycling career that has even been remotely close to killing me other than when being overtaken. No, I don't have the exact numbers but I gotta say the chances of me being hit from the side are a million to one. The chances of someone running me over from behind or right-hooking me if I did not have a mirror, use my ears, and pay strict attention, is easily one in ten thousand. Some days it seems like the flip of a coin with every pass.

njkayaker

Things are going to be more accurate if you can get data for subpopulations.

I think that for the aggregate population, hours are better for comparisions. It might not be better for comparing subpopulations.

Which why I said this:

njkayaker

Many (most?) people who ride likely don't ride enough for it have any impact on their mortality.

wphamilton

That's the difficulty. Although we can get some data for commuting miles, and we can break it down geographically if one wants to go to the trouble. But the related data for accidents, currently not possible as far as I'm aware. The best we can do is interpolate from more general data, which can result in at best just ballpark numbers.

I don't disagree with that.

My only point here is that risk on a per mile basis isn't necessarily a bad comparison.

CommuteCommando

Point taken. I was obese and suffering chronic heart disease, so in a way I am safer riding the bike. I was of course talking about accident mortality rates. As far as how I die goes, I find dying quickly hitting the pavement after being struck by a fast moving death machine, preferable to dying slowly, as diabetes and heart disease torture me.

I am of course, looking to die much later, Like my old man who was busting concrete with a sledge hammer while doing home repairs well into his eighties.

njkayaker

I suspect that drivers, on average, are commuting much longer distances that cyclists (basically, both might spend the about same amount of time commuting). Plus, in urban evironments, driver speed may be reduced by traffic. The risk might, in the aggregate, scale better with hours spent doing the commute. We don't really know.

Yes. Which is why I said this (not referring to you):

I didn't claim that it was necessarily a bad comparision. And I pointedly wasn't talking about comparing subpopulations.

We really don't have enough good data to make any good comparision.

wphamilton

But if you're going to analyze it at all, you've got to start with some way of grappling with the data you do have.

There have been a few decent studies on overall mortality rates; I think a couple have been linked in this thread. One of them had a large sample population in England if I recall correctly, and the general types of cycling identified. Commuter, utility, recreational.

Hypothetically you could normalize their data with respect to mileage for each category, and compare that against fatal accident statistics involving motor vehicles in that area, and you'd have a pretty decent result in my opinion.

njkayaker

No one is required to analyse crappy data.

Keep in mind that I'm criticising drawing conclusions that are "certain" from poor data.

One problem with research is that people will publish whatever they come up with whether or not what they come up with is real or useful.

There's a general assumption that if something is published, it's necessarily valid. That isn't true at all.

Which might, of course, not apply to people in the US.

wphamilton

I'd say all three surmises are almost certainly correct, or at least in the ballpark.

It might be, and we don't know. That's why I resorted to looking at the specific risk situations, for which we do have some data, and tried to analyze the associated risk with respect to distance and time. Nothing certain can come from that, but you can perhaps find a basis of comparison with more confidence than guesswork.

My reasoning on the intersections (including driveways) is simply that the only difference in risk is cross traffic, including right and left hooks, so that it matters less long you're exposed in approaching and crossing, having generally the same risk for an intersection whether you're averaging 10 mph or 20 mph for example. On a per hour basis you'd assume double the risk at the lower average speed, which makes less sense to me than simply presuming a risk at each one and summing them. Which would scale generally with miles traveled.

Some other risk factors logically scale better with the time exposed to them. Maybe it would be better to investigate each type of risk independently - but we can't, so inevitably there has to be some compromise.

njkayaker

One can compromise too much (beyond the point real understanding).

I don't have a problem with trying to perform analyses (or discussing those attempts) but some people here are way too certain about what those analyses really mean.

Since it appears that drivers have more difficulty seeing/expecting cyclists at intersections, the intersection risk of driving at 20 mph could be less than the risk of bicycling at 10 mph. And a person might fair better in a 20 mph car collision. Anyway, cycling commuters are likely going to be riding much shorter distances on average that driving commuters.

enigmaT120

Average car commute is 12.6 miles. The source didn't have numbers for the average bike commute, but I suspect it is shorter than that from what I've seen in the commuter forum.

https://www.fhwa.dot.gov/policy/2010cpr/execsum.htm

wphamilton

Other related information, average travel time for bicycle commutes is 19.3 minutes, and workers not walking or working from home average 25 minutes. From US Census Modes Less Traveled—Bicycling and Walking to Work in the United States: 2008–2012 These reports do not include distance traveled but for bicycles it's certainly less than the average 12.6 miles for cars (Likely under 4 miles given normal commuter cycling speed). I'm sure I've seen a census survey with that (cycling commute distance) information, maybe I can recall it.

So the first two surmises of njkayaker are backed by the Census and Dot data. There are 760,000 bicycle commuters in the USA (again Census figures, the definition would be in the report above). If we could find some valid data regarding commuting accidents we'd be on solid ground.