Bike Forums

Bike Forums (https://www.bikeforums.net/forum.php)
-   Advocacy & Safety (https://www.bikeforums.net/advocacy-safety/)
-   -   The Helmet Thread 2 (https://www.bikeforums.net/advocacy-safety/976893-helmet-thread-2-a.html)

njkayaker 12-02-20 09:56 AM


Originally Posted by Koyote (Post 21814864)
I’ve long been amazed at the paucity of data on cycling safety. For instance, reliable studies on the efficacy of helmets, daytime running lights, etc.

The events are relatively rare and there's less economic value in pursuing the studies.

Seems expected to me.

mr_pedro 12-02-20 01:19 PM


Originally Posted by njkayaker (Post 21814972)
I took that into account.

At the rate of the fatalities in the Netherlands, the US would have 4000 cyclist deaths (rather than 800).

Ok, how did you get to 4000?


Even that's not fair because the cycling (as you pointed out) is different too.
That is how it works, you scale the numbers by distance travelled and any differences left can be attributed to the cycle environment/behavior in both countries



Using these numbers, it's

1.12E-08 deaths/mile for the US.

1.22222E-07 deaths/mile for the Netherlands (10 times more).
Sorry the 5.4 billion number I had quoted is actually car miles per million people. In NL we drive about half the miles per person compared to the US, for a total of 92.3 billion miles. The factor of 1.5 still stands.

CargoDane 12-02-20 01:49 PM

Miles-travelled is the only one that makes sense.
If you do it by population, rather than how many miles were travelled per fatality, any niche activity will look safer than it is.

If you do it by population, you don't even take into account how many actually do the activity and compare that. Doing it per miles-travelled does in a roundabout way.
No one who has ridden both in the Netherlands (or Denmark) and the US will say that it is safer to ride in the US. There's a huge, huge difference.

njkayaker 12-02-20 03:27 PM


Originally Posted by mr_pedro (Post 21815316)
ok, how did you get to 4000?


Originally Posted by njkayaker (Post 21814726)
​​​​​​203 cyclist road fatalities with 17 million people in the netherlands in 2019.

857 cyclist fatalities (2018) with 328 million people in the us.
​​​​​

203/17,000,000*330,000,000 = 3940.


Originally Posted by mr_pedro (Post 21815316)
Sorry the 5.4 billion number I had quoted is actually car miles per million people. In NL we drive about half the miles per person compared to the US, for a total of 92.3 billion miles. The factor of 1.5 still stands.

That makes more sense.
​​​​​​​

mr_pedro 12-02-20 03:41 PM


Originally Posted by njkayaker (Post 21815501)
203/17,000,000*330,000,000 = 3940.

Ok, I get your point. You acknowledge that it is safer to ride your bike in NL vs US, but want to stress there are still quite some people dying on bikes in NL.

njkayaker 12-03-20 10:55 AM


Originally Posted by mr_pedro (Post 21814765)
​​​​The only way to check the relative mortality is by comparing deaths per mile.

No, that's not true.

A person is going to be riding the average number of miles. That average number is different between the two countries.

On average, a person is much more likely to die while riding a bicycle in the Netherlands.


Originally Posted by mr_pedro (Post 21815528)
Ok, I get your point. You acknowledge that it is safer to ride your bike in NL vs US, but want to stress there are still quite some people dying on bikes in NL.

No, it's only less risky if you ride less than the average miles. But, since we are talking about averages, you won't be.

mr_pedro 12-03-20 11:50 AM


Originally Posted by njkayaker (Post 21816547)
No, that's not true.

A person is going to be riding the average number of miles. That average number is different between the two countries.

On average, a person is much more likely to die while riding a bicycle in the Netherlands.


No, it's only less risky if you ride less than the average miles. But, since we are talking about averages, you won't be.

With that logic you would say cycling is less risky even in a country of 400 million people with only 100 cyclist that went out on the bike for only 1 day in a year of which 50 died on the bike that year. Not sure if you don’t understand or just want to argue, but either way it is fine to leave it at that.

elcruxio 12-05-20 04:21 AM


Originally Posted by njkayaker (Post 21816547)
No, that's not true.

A person is going to be riding the average number of miles. That average number is different between the two countries.

On average, a person is much more likely to die while riding a bicycle in the Netherlands.


No, it's only less risky if you ride less than the average miles. But, since we are talking about averages, you won't be.

Probably the best way to compare risk between different modes of transport and between different countries is accidents or in this case deaths per time spent doing said activity. Deaths per distance is inherently inaccurate as different modes of transport have wildly varying average speeds. Time spent however is somewhat difficult to measure accurately.

deaths per population however is the absolutely wrong way of comparing transport safety. If deaths per population was in any way a proper measure, NASA would have swapped their manned space mission launches to Mexico a long time ago. Lots of space mission related deaths in the US. I'm guessing zero in Mexico. Ergo, space flying in the US is dangerous while in Mexico it's incredibly safe. When you consider it with deaths per launch, distance or time spent it's a very different proposition.

njkayaker 12-05-20 11:49 AM


Originally Posted by mr_pedro (Post 21816636)
With that logic you would say cycling is less risky even in a country of 400 million people with only 100 cyclist that went out on the bike for only 1 day in a year of which 50 died on the bike that year. Not sure if you don’t understand or just want to argue, but either way it is fine to leave it at that.

???

If you have to walk to school and you move from where you are a block a way to a place that is 4 miles away, any risk there is in walking increases.

If you move from the US to the Netherlands, you will be riding a lot more on average.

Comparing the risk per mile hides that increase.

njkayaker 12-05-20 11:59 AM


Originally Posted by elcruxio (Post 21819194)
Probably the best way to compare risk between different modes of transport and between different countries is accidents or in this case deaths per time spent doing said activity.
Deaths per distance is inherently inaccurate as different modes of transport have wildly varying average speeds. Time spent however is somewhat difficult to measure accurately.

It's one way. It's not necessarily "best" always. The risk per mile or time hides the fact that people in the Netherlands spend much more time cycling.

The risk per whatever might be lower but the exposure is much more.

It looks like you are more likely to die on a bicycle and less likely to die in a car in the Netherlands.


Originally Posted by elcruxio (Post 21819194)
deaths per population however is the absolutely wrong way of comparing transport safety. If deaths per population was in any way a proper measure, NASA would have swapped their manned space mission launches to Mexico a long time ago. Lots of space mission related deaths in the US. I'm guessing zero in Mexico. Ergo, space flying in the US is dangerous while in Mexico it's incredibly safe. When you consider it with deaths per launch, distance or time spent it's a very different proposition.

No.

The risk of doing something can't be equivalent to not doing something. It's a "divide by zero" sort of situation. You are saying that not having money makes you infinitely wealthy.

elcruxio 12-05-20 01:23 PM


Originally Posted by njkayaker (Post 21819624)
???

If you have to walk to school and you move from where you are a block a way to a place that is 4 miles away, any risk there is in walking increases.

Sure. Why not. Not really relevant but whatever.


If you move from the US to the Netherlands, you will be riding a lot more on average.

Comparing the risk per mile hides that increase.
That's not again not what the discussion is about. This is major league goalpost shifting. The discussion was about risk of cycling in different countries and you seem to be saying that cycling in the Netherlands is more dangerous than in the US. Of course a direct comparison is difficult, because the US is pretty big and the Netherlands aren't. But even then the proposition that cycling was safer in the US is laughable. Have you cycled in the Netherlands? I haven't in the US, but I can see enough videos about it to know I'd never even attempt it.


Originally Posted by njkayaker (Post 21819636)
It's one way. It's not necessarily "best" always. The risk per mile or time hides the fact that people in the Netherlands spend much more time cycling.

It doesn't actually. But cool that you brought that up. It's already a pretty well known phenomenom that more cyclists makes cycling safer so more time spent on the bike in general means less accidents and less deaths.


The risk per whatever might be lower but the exposure is much more.
Which doesn't matter if the risk is significantly lower. Not going to make an example because percentages are hard when you make percentage chains, but if you have a tiny risk and large exposure the risk is still smaller than a massive risk and tiny exposure.


It looks like you are more likely to die on a bicycle and less likely to die in a car in the Netherlands.
In 2019 that wasn't the case, but the numbers are pretty close. That doesn't however mean that cycling in the Netherlands is dangerous. It means that traffic there is incredibly safe.
in the year 2019 US motor vehicle fatalities were three times more than the whole traffic fatality rate of the Netherlands. If you compare just motor vehicle fatalities US fatalities were eight fold to those of the Netherlands.

So, you know, traffic in the Netherlands is safer.



No.

The risk of doing something can't be equivalent to not doing something. It's a "divide by zero" sort of situation. You are saying that not having money makes you infinitely wealthy.
I don't see why not. But if I have to use a country that has actually done manned missions then NASA should start doing all their launches from China. Much safer than the US. I haven't studied statistics but even I know that deaths per population is good for only one thing. Literally deaths per population. No other factors. Just that. Deaths per population in an activity is a useless metric.

njkayaker 12-08-20 09:47 AM


Originally Posted by elcruxio (Post 21819741)
That's not again not what the discussion is about. This is major league goalpost shifting.

It's exactly what is about. No goal shifting at all.


Originally Posted by elcruxio (Post 21819741)
Which doesn't matter if the risk is significantly lower. Not going to make an example because percentages are hard when you make percentage chains, but if you have a tiny risk and large exposure the risk is still smaller than a massive risk and tiny exposure.

The risk in the Netherlands isn't tiny. It's small. The equivalent indicates that 4000 people would die in the US if they rode like the people in the Netherlands do (rather than 800).

elcruxio 12-09-20 05:20 AM


Originally Posted by njkayaker (Post 21823556)
It's exactly what is about. No goal shifting at all.


The risk in the Netherlands isn't tiny. It's small. The equivalent indicates that 4000 people would die in the US if they rode like the people in the Netherlands do (rather than 800).

Well no. Because exposure matters. Consider this. If you have a person who drives for a living, ie. six to seven hours a day behind a wheel and a person who drives once a year for five miles, which is more likely to get into a traffic accident of any sort?

So in reality exposure matters. If you cycle more, you're more likely to get into an accident. If you drive more, you're more likely to get into an accident. If you live more, you're more likely to get into an accident. What mitigates traffic accident risks is external factors such as infrastructure, traffic rules and culture.

So let's get into the very bad statistics since there aren't good numbers available and neither of us is a statistician.

If we account for exposure then if the people in the US rode bikes like the Dutch do, then the number of fatalities would not be 4 000. It would instead be around 16 000. Strangely enough the US and the Dutch ride around the same amount of trips per yer, ie. around 4 billion. Depending on what number you use the Dutch number might actually be closer to five, but we'll go with equivalent numbers. Now since the amount of trips is around the same we can directly compare the amount fatalities. In the Netherlands it's around 200 per year. In the US it's around 850 per year. So in the Netherlands you get around 200 fatalities per 4 billion trips. In the US you get around 850 fatalities per 4 billion trips.
But in the US there's 19 times more people. So if the US did in fact ride as much as the Dutch you'd need to multiply that fatality number with 19, getting a fatality rate of around 16 000.

Of course none of that is really that simple. If the US rode as much as the Dutch do, there would likely be significantly less fatalities purely because of the phenomenom critical mass, ie. US drivers would be more cognizant of cyclists on the road and thus give them more regard and space.
What I could not factor in was kilometers ridden or time spent in the saddle because I could not find those numbers from the US and even with in the case of Netherlands getting the time in the saddle number is pretty difficult.

Onward!

The Netherlands is probably one of the safest traffic regions in the world. Their traffic fatalities are tiny in general. Both driving risks and cycling risks are in fact tiny in the Netherlands. I can use the world tiny, because the Netherlands is the safest country to cycle in. I don't know what you think of how safe it is to drive a car in the US, but it's around four times safer in the Netherlands. Actually I think that's the wrong phrasing but you get a quarter of motor vehicle fatalities in the Netherlands when compared to the US when controlling for kilometers driven.
So with that potentially wrong phrasing I can conclude that it is four times safer to drive in the Netherlands (which means driving in the US isn't cataclysmic) and nineteen times safer to ride a bicycle in the netherlands when compared to the US.

I hope no actual statistician reads this...

2wheelfelicity 12-17-20 01:54 AM

In the event of a crash, a helmet will protect your head. This doesn't mean it will save you every time, either from death or serious injury, only that it will rarely if ever make it worse. From another perspective, there is statistically proven safety in numbers and helmets can represent a barrier either for people who can't afford one or do not want to wear one. Helmets should always be a choice and drivers should be subjected to significantly greater road safety awareness considering the damage they can do. Of course, bikes cause accidents too, but not nearly as often, and typically no where near the severity.

wphamilton 12-23-20 10:55 PM


Originally Posted by elcruxio (Post 21824833)
Strangely enough the US and the Dutch ride around the same amount of trips per yer, ie. around 4 billion. Depending on what number you use the Dutch number might actually be closer to five, but we'll go with equivalent numbers. Now since the amount of trips is around the same we can directly compare the amount fatalities.

What is the average trip distance in The Netherlands and the US? You can't correctly quantify exposure without it, when you're citing the number of trips.

mr_pedro 12-24-20 12:54 AM


Originally Posted by wphamilton (Post 21846283)

What is the average trip distance in The Netherlands and the US? You can't correctly quantify exposure without it, when you're citing the number of trips.

The average trip distance in NL is about 3km.
Another difference is that I suspect the US to have a larger fraction of recreational rides done in parks.

Maybe we can look at it from a different perspective, what we know reasonably well is the number of fatalities and population size. So if we would scale up the Dutch fatalities to the US size we would get 4 times as much fatalities as we currently do in the US.

So what we now need to ask is if the Americans ride more or less than 25% of what the Dutch ride?
You only need to look at the streets in US and NL cities to tell that the US does not even come close to having 25% of the Dutch cycling density.
If you have any doubts, just consider that 25% of the Dutch use their bikes for commuting. Even ignoring public transport that means 1 bicycle in morning traffic for every 3 cars.

curbtender 12-24-20 10:34 AM

And if you factor on the amount of drinks consumed before heading home from the local tavern...

wphamilton 12-24-20 04:07 PM


Originally Posted by mr_pedro (Post 21846350)
The average trip distance in NL is about 3km.
...
So what we now need to ask is if the Americans ride more or less than 25% of what the Dutch ride?
.

We'd be multiplying too many uncertainties in that chain, for it to be reasonable to me. The confidence interval shrinks to almost nothing (meaning we wouldn't know that the answer was right or even close to right).

I asked partly because I don't have any absolutely solid data on the average length of bike trips in the USA and Netherlands, and partly because what I do have implies 3-4 times longer on average in the USA. Which would be 3-4 times the exposure.

The closest I have that we can be reasonably confident with is the average commute time, about 20 minutes in the USA and quite a bit less in Netherlands. But even that is skewed because it's an average, and comprised of a lot of short commutes balanced by a small number of very long ones. Looking at all the short commutes would give us a better picture, and they may or may not still be considerably more than in the Netherlands AFAIK. And we can't generalize commutes to all trips, so my data is less meaningful also.

In short I don't think it's been demonstrated that based on exposure to traffic or other dangers, cycling in the Netherlands is less risky or more risky than cycling in the USA.

njkayaker 12-24-20 06:59 PM


Originally Posted by elcruxio (Post 21824833)
Well no. Because exposure matters. Consider this. If you have a person who drives for a living, ie. six to seven hours a day behind a wheel and a person who drives once a year for five miles, which is more likely to get into a traffic accident of any sort?

Someone who drives for a living, can't really choose to avoid the increased exposure. Someone living in the Netherlands can't completely choose to avoid the increased exposure either.

If you compare accidents per mile, the professional will likely have a much lower number than the person who drives once a year.


Originally Posted by elcruxio (Post 21824833)
So in reality exposure matters. If you cycle more, you're more likely to get into an accident. If you drive more, you're more likely to get into an accident. If you live more, you're more likely to get into an accident. What mitigates traffic accident risks is external factors such as infrastructure, traffic rules and culture.

Which is what I said a while ago.


Originally Posted by elcruxio (Post 21824833)
If we account for exposure then if the people in the US rode bikes like the Dutch do, then the number of fatalities would not be 4 000. It would instead be around 16 000.

??? The 4000 is scaled from the death rate in the Netherlands. It accounts for the exposure!


Originally Posted by elcruxio (Post 21819741)
I don't see why not. But if I have to use a country that has actually done manned missions then NASA should start doing all their launches from China. Much safer than the US. I haven't studied statistics but even I know that deaths per population is good for only one thing. Literally deaths per population. No other factors. Just that. Deaths per population in an activity is a useless metric.

You are contradicting yourself if "in reality, exposure matters".

mr_pedro 12-24-20 11:47 PM


Originally Posted by wphamilton (Post 21847197)
We'd be multiplying too many uncertainties in that chain, for it to be reasonable to me. The confidence interval shrinks to almost nothing (meaning we wouldn't know that the answer was right or even close to right).

I asked partly because I don't have any absolutely solid data on the average length of bike trips in the USA and Netherlands, and partly because what I do have implies 3-4 times longer on average in the USA. Which would be 3-4 times the exposure.

The closest I have that we can be reasonably confident with is the average commute time, about 20 minutes in the USA and quite a bit less in Netherlands. But even that is skewed because it's an average, and comprised of a lot of short commutes balanced by a small number of very long ones. Looking at all the short commutes would give us a better picture, and they may or may not still be considerably more than in the Netherlands AFAIK. And we can't generalize commutes to all trips, so my data is less meaningful also.

In short I don't think it's been demonstrated that based on exposure to traffic or other dangers, cycling in the Netherlands is less risky or more risky than cycling in the USA.

:) I actually know what a confidence interval is and you said the opposite of what you mean, i.e. small confidence intervals imply a very high degree of certainty.

But since we don’t have much US data on cycling exposure, indeed we can’t put exact figures on deaths per mile. The 25% figure I mentioned needs to be more like 20% because there are 850 cycling deaths in the US vs 4000 if you scale up NL deaths. So would you agree with the statement that cycling is more dangerous in the US if people in the US ride less than 20% of the distance they do in NL?

wphamilton 12-25-20 01:38 AM


Originally Posted by mr_pedro (Post 21847692)
:) I actually know what a confidence interval is and you said the opposite of what you mean, i.e. small confidence intervals imply a very high degree of certainty.

But since we don’t have much US data on cycling exposure, indeed we can’t put exact figures on deaths per mile. The 25% figure I mentioned needs to be more like 20% because there are 850 cycling deaths in the US vs 4000 if you scale up NL deaths. So would you agree with the statement that cycling is more dangerous in the US if people in the US ride less than 20% of the distance they do in NL?

Bad choice of words on my part, because I'm not talking about statistics. Just the multiplying of variables each having a measure of uncertainty.

The statement you ask about is more correct, but not yet one I could agree with. There is yet another factor involved with "exposure": speed. The faster you travel, the fewer interactions you'd have with same-direction travel.

mr_pedro 12-25-20 02:01 AM


Originally Posted by wphamilton (Post 21847745)
Bad choice of words on my part, because I'm not talking about statistics. Just the multiplying of variables each having a measure of uncertainty.

The statement you ask about is more correct, but not yet one I could agree with. There is yet another factor involved with "exposure": speed. The faster you travel, the fewer interactions you'd have with same-direction travel.

Sure, that is the difference between measuring exposure by time or by distance travelled. Both are reasonable measures. Using time would only skew results towards more dangerous in US as speeds in NL are low, about 10 mph.

elcruxio 12-25-20 03:01 AM


Originally Posted by njkayaker (Post 21847436)
Someone who drives for a living, can't really choose to avoid the increased exposure. Someone living in the Netherlands can't completely choose to avoid the increased exposure either.

They can if they choose another profession. Also could be someone who just commutes to work using a car.


If you compare accidents per mile, the professional will likely have a much lower number than the person who drives once a year.
Goalpost shift and is that actually even true?


Which is what I said a while ago.
Did you? Your definition of exposure seems a bit strange.


??? The 4000 is scaled from the death rate in the Netherlands. It accounts for the exposure!
It doesn't, because it doesn't actually account for exposure. Actually accounting for exposure is difficult as the information from the US is patchy at best. But if you account for exposure, ie. if people in the US cycled as much as the Dutch do, then the death rate would be closer to 16 000 than 4 000. This is because cycling in the Netherlands is vastly safer than in the US.



You are contradicting yourself if "in reality, exposure matters".
Yes well that was kinda the point of that silly absurd example. I hoped it would be nonsensical enough that you'd catch the point behind it.


Originally Posted by mr_pedro (Post 21847749)
Sure, that is the difference between measuring exposure by time or by distance travelled. Both are reasonable measures. Using time would only skew results towards more dangerous in US as speeds in NL are low, about 10 mph.

Is there a studied number of the average speeds of the dutch cyclist? I know they ride bikes which seem slow but holy cow can the young folks punish those bikes to some absurd speeds. When I was last there I couldn't keep up with my touring bike. And I'm not that slow even fully loaded.

mr_pedro 12-25-20 03:27 AM


Originally Posted by elcruxio (Post 21847758)

Is there a studied number of the average speeds of the dutch cyclist? I know they ride bikes which seem slow but holy cow can the young folks punish those bikes to some absurd speeds. When I was last there I couldn't keep up with my touring bike. And I'm not that slow even fully loaded.

Yes regularly you will find two strips across the bike path about 3 ft apart. This is used to measure speed and count the bicycles passing.

For example in this article the speeds between provinces are compared with numbers to the decimal place:
https://www.nhnieuws.nl/nieuws/17365...-van-nederland

There reason the average speed is so low is because these are people in regular clothes using the bike for daily transportation needs. Also a much larger part than in the US, consists of children aged 10-16 and elderly above 65.

wphamilton 12-25-20 08:09 AM


Originally Posted by mr_pedro (Post 21847749)
Sure, that is the difference between measuring exposure by time or by distance travelled. Both are reasonable measures. Using time would only skew results towards more dangerous in US as speeds in NL are low, about 10 mph.

"Speeds are low" is another example of assumptions based on too little, and too general. We don't actually know what the "speeds" are in the US. We also don't know how those speeds are distributed according to various types of trips.

Neither exposure by distance nor time spent in travel are reasonable measures of exposure to risk, especially not when those measures are averages. If you want to know their actual exposure to traffic dangers, there is no adequate proxy other than observing it directly in a representative sample. We cannot draw conclusions about where it is more dangerous based on our ideas of the distances and times spent on our bikes.


All times are GMT -6. The time now is 06:57 AM.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.