That may depend on how "serious accidents" are defined. Can you cite the reference for this understanding about "serious accidents"?

If you go back to what I actually said and compare it with what you said I said, you may see some very stark differences. Like: where did I ever claim that safety classes are effective for those who do not take them?

Here's a great example of you easily misunderstanding another simple quote:

Well, gosh, that's not what he was saying at all and you are, not surprisingly, misrepresenting his argument. If I were to paraphrase the post you quoted in your terms, it would be along the lines of: "Helmets are useless in collisions where they are useless, therefore they are useless in all collisions where they are useless." But of course you left out a critical qualifier in order to match what you wanted to argue rather than what was actually said.

It's a standard type of classification in the various statistical studies. Usually related to the type and degree of trauma. I'd have to show you the specific studies and how it's phrased in each, but that would be kind of pointless to satisfy a snipe, no?

You may consider any skepticism about your "understanding" as unwelcome but the objection to your understanding about the relative risk factor to bicyclists from hit from behind accidents is long standing and dates back to John Forester's imaginative interpretations of cherry picked accident studies to reach the same conclusion, i.e. that hit from the rear bicycle accidents are not that significant when evaluating comparative cycling risk. He usually ignored accident severity as well as exposure to the specific hazard data when it was convenient for reaching conclusions that supported his Vehicular Cycling agenda. Is your "understanding" any more reality based than his?

It's not that - I just felt it to be a trivial question posed in order to irritate me. The relative incidents of types accidents have been looked into and aren't really controversial.

It seems to me that you post provocative/controversial "understandings" but do not want any response but a high five confirmation. You are hardly alone in that preference, BF has lots of posters who cannot handle skepticism of flaky claims or opposing opinions of their views, especially if it is not IAW current Bicycling Correctness™ views held by BF mavens.

Really? You think that "hit from behind are the least common serious accidents" is not controversial?

I'm fine with opposing viewpoints and I invite you to substantiate whatever it is you disagree with me about.

There's a shocker.

Recent research indicates that "hit-from-behind" is actually a significant contributor to cyclist fatalities. I'll see if I can find the link - it's one of the reasons I no longer ride on the road.

Re. speed, I suppose we are all products of our environment. Here in south Orange County, CA., speed limits of 45+ are common on surface streets, which means that 60 MPH isn't at all unusual. That's what I am thinking of when discussing high-speed vehicles - and when I'm making fun of people who believe their bicycle helmets will prevent their deaths when struck by such vehicles.

<Edit> It's a LAB study, claiming that 40% of cycling deaths are due to "hit from behind". http://bikeleague.org/content/new-re...cyclist-counts

You have a proven track record of either not understanding or intentionally distorting other peoples' arguments. Your post above is simply one more example.

In this one What are the Dangers in Terms of Cycling Safety?| Share The Road come from behind are only 11.9% of the accidents, and that's higher than what we usually see.

The difference is probably that you're still restricting your consideration to fatal accidents with the LAB report. There are about 6-700 bicycle fatalities per year http://www-nrd.nhtsa.dot.gov/Pubs/812018.pdf, but about 100 times that many visits to emergency rooms with head injuries alone.

How many of those ER visits are "serious" is fuzzy, but with 100 time as many it doesn't take much of it to make the 40% a significantly smaller number compared to serious accidents.

(For the sake of accuracy, I should mention that the LAB report is criticized for limiting their data set to pubic sources: newspaper, tv and blogs, though to be fair they captured information about 75% of the fatalities.)

For starters see this synopsis/interview about the recent League of American Bicyclist report on fatal accident statistics.
http://bikeleague.org/sites/default/...port_final.pdf and
Q&A: New League study challenges assumptions about fatal bike crashes | Bicycle Retailer and Industry News

Below are a few other sites that refer to the controversial nature of your understanding about the results and frequency of hit from behind bicycling accidents.
8 takeaways from the Bike League's study of cyclist fatalities - Greater Greater Washington
Are more cyclists getting hit from behind than ever before? | Bike Delaware Inc.

Granted that these articles/reports only discuss fatalities and not injuries, and you could have an understanding that serious injuries (however reasonably defined) will not track, correlate or correspond in any way with the fatality rate, but I will give you more credit than that.

Another point that should be considered is that the exposure rate to hit from behind accidents is reduced by the fact that many, if not most cyclists take steps to reduce that exposure whenever possible by riding on shoulders, sidewalks, as far to the right as possible, etc. Granted that bicyclists are not 100% free of the risk of hit from behind accidents by such countermeasures but the risk from that type of accident event is reduced by their cycling behavior. That hit from behind fatalities occur anyway at such a high frequency should give cyclists who do take the lane pause for thought.

Perhaps your understanding of the relative unimportance of hit from behind accident derived from decades old John Forester brand pronouncements on the subject that discounted any consideration of accident severity or exposure to specific type of bicycling hazards.

What makes you think the serious head injuries are not occuring with high frequency as a result of hit from behind collisions?
Do you still maintain that your understanding is not controversial?

Even the LAB report refers to my understanding as the generally accepted one, so no it's not controversial.

As for the first, you support my point. If that were the case, then the effectiveness of helmets cannot be ruled out because the victim dies anyway, as Six Jours suggests.

OK, got it. That is your understanding and you are sticking to it.

No, just refuting your unsubstantiated notion that what I wrote was controversial.

Did you dispute the reasoning that 40% of all fatal accidents (or around 250 of them) is only 0.3% of ER accidents involving head injury?

Nothing to dispute since there is no reasoning; the two data sets have no relationship to each other.

They both include "serious accidents".

Only if you assume all trips to an ER is the result of a serious accident, and that any and all injuries to include boo-boos and scratches reported to an ER attendant are defined as a serious injury.

"Only if" you assume some of the trips to ER involve serious accidents. Not "all" of them.

I've already gone over this. I said that the proportion of ER visits were "serious" would be fuzzy, but if you have 100 ER visits (head injuries alone) for every fatality it's safe to say that a number of them involve serious injury. I've verified this assumption by looking at accident stats, but I don't really need to pull them up and summarize them for this one obvious point, do I?

670 fatalities more or less. 67,000 ER visits with head injury. Do you seriously accept that it proves that helmets are useless in all high-speed car-bike interactions, that a couple of hundred of them were hit-from-behind fatalities? That's the case that you're arguing for here.

I can't recall my posting a word about helmets in this current series of posts about your "understanding" of the frequency/seriousness of hit from behind accidents.

That made no sense to me at all, sorry. "Do you seriously accept that it proves that helmets are useless in all high-speed car-bike interactions, that a couple of hundred of them were hit-from-behind fatalities? "

What does that have to do with "my understanding" (which incidentally I proved is neither controversial nor different from the literature, rendering moot whatever point you're trying to make)

Understanding,
Moot,
You.

Merry Christmas.

I've been talking about the ability of a helmet to save lives - in particular, to save the lives of cyclists struck by speeding (45+ MPH) vehicles. The "serious accident" stuff hasn't been adequately defined here, and is irrelevant to my line of discussion anyway. I'm not sure why you bring it up with me.