Is cycle helmet promotion warranted? DK v NL data

[Jdsk]

The paper provides the opportunity for anyone from Denmark to explain why any other factors could have discouraged cycling. It shows cycling levels in some main cities increasing and I gather they have invested in cycling infrastructure. .

I think there is another clear factor here. Denmark has been doing infrastructure but simply not as fast nor as well as the Dutch. Regardless of whatever Colville-Andersen likes to claim via his blatantly rigged Copenhagenize index, Danish provision isn't a patch on the Dutch and this is reflected in the demographics seen cycling as with fewer very young, very old etc Danes getting about on bikes.

Both countries have seen, much as any country, a continuing shift to cars in more rural areas due to ever cheaper real terms costs of motoring, increasing disposable incomes, lack of safe cycle infra and inevitably poorer PT provision. The Dutch however have continued to really squeeze motoring in urban areas and have better junction designs where drivers and cyclists do need to interact, hence the national mode share has remained stable with urban increases offsetting the rural drop. Danish urban shares have been rather more stable at best with failures to really capitalise on earlier gains.

...

Thanks for that.

The paper should include discussion of possible confounders. It mentions "other changes" but doesn't list them. And the caution in its discussion of causation has been changed by Steady rider in this thread to "strongly indicates".

But apart from possible confounders it doesn't even include anything about the "promotion" in either country, and that's its major topic. Only an unevidenced and unreferenced assertion that it's different between them.

Jonathan

[Steady rider]

https://www.cyklistforbundet.dk/english/use-of-helmet/ The paper mentions 'Denmark has for some years promoted helmets Cyklistforbundet (2022)'

Wearing rate for children - Almost 90 % of the participants in Bike to School wear helmet.

So how much pressure was applied and what are the numbers and any changes?

[Jdsk]

https://www.cyklistforbundet.dk/english/use-of-helmet/ The paper mentions 'Denmark has for some years promoted helmets Cyklistforbundet (2022)'

Wearing rate for children - Almost 90 % of the participants in Bike to School wear helmet.

So how much pressure was applied and what are the numbers and any changes?

Yes, that's the reference in the paper.

But that contains no information on what "promotion" means in practice, or whether it has changed. And the paper contains no information at all about what has been done in the Netherlands either in the text or in a reference.

The whole point of the paper is the effects of the different policies on "promotion". And there is precisely zero information on the difference between the policies. Only an unevidenced and unreferenced and undiscussed assertion that they are different.

Jonathan

[Steady rider]

Yes more details regarding DK and NL would have improved the paper, but space was limited. https://road-safety-charter.ec.europa.e ... -trafik_en
The link shows Denmark had definite plans to increase helmet wearing for children. The plans stemmed from 2004 and accident data is mentioned in the paper,

Denmark has reported reduced cycling activity and the accident data shows the largest reductions from 2004 to 2020 were in the 0-17 age range, Danish Road Directorate (2022).

Denmark also produced a Viking add, https://www.youtube.com/watch?v=oDscjFif6jg

https://discerningcyclist.com/why-do-du ... r-helmets/ The Netherlands by comparison still have low levels of helmet wearing.

In the UK when one school insisted that children wear helmets it resulted in expelling some children.

[Jdsk]

Yes more details regarding DK and NL would have improved the paper, but space was limited.

It's not a matter of "more details" but of any details at all.

Your opening post includes:

"It appears helmet promotion is a main reason for the difference."

But the paper includes no information on any differences in "promotion" between the two countries.

Jonathan

[Steady rider]

The paper states,

Denmark has for some years promoted helmets Cyklistforbundet (2022) and comparing changes in cycling levels may reflect helmet promotion. Table 4 shows information for the two countries.

The reference includes,

Campaigns are the way to go
The Danish Cyclists’ Federation has spent a lot of resources on campaigns that among other things promote helmet wear. This has resulted in a significant increase in the number of cyclists who wear helmet.

Our campaign, Bike to School is a good example:

Almost 90 % of the participants in Bike to School wear helmet

.

https://bicycledutch.wordpress.com/2019 ... dutch-way/
Details from the Netherlands that came to light suggested few wear helmets and they did not have the same policy.

[simonineaston]

Why do people take their helmet with them and then hang it off their handlebars? Never understood that one...

[Jdsk]

The paper states,

Denmark has for some years promoted helmets Cyklistforbundet (2022) and comparing changes in cycling levels may reflect helmet promotion. Table 4 shows information for the two countries.

Table 4 provides no information on promotion.

The paper contains no information on differences in promotion between the two countries. But this thread is about promotion. Without information on differences in promotion you can't attribute any differences in rate of cycling to differences in promotion.

Jonathan

PS: Any response to the discussion of confounders upthread?

[Jdsk]

https://bicycledutch.wordpress.com/2019 ... dutch-way/
Details from the Netherlands that came to light suggested few wear helmets and they did not have the same policy.

That anecdotal essay contains no information on promotion or its absence in the Netherlands.

Jonathan

[Steady rider]

https://dutchcycling.nl/
It shows the approach taken.

http://www.copenhagenize.com/2008/08/he ... danes.html

It mentions the differences that goes back some years.
Data on km cycled by age group per year from about 2000 for NL and DK could be compared with the helmet promotion in DK.
More data would be helpful.

[Jdsk]

More data would be helpful.

You're right. But the problems with Clarke's paper aren't limited to there being inadequate data. The whole approach prevents any reliable inference about the effects of promotion on anything.

1 The Methods section doesn't say what was done. You've told us that some studies were selected and others rejected on subjective grounds but that no-one knows the criteria which were used. This approach is completely vulnerable to selection bias and confirmation bias.

2 There is no information on differences in promotion between the two countries, the key point under consideration.

3 There is no discussion of possible confounders.

Addressing each of these (and more) is essential to any observational study. And there are widely available guidelines available which should be used before publication and which would remove these basic problems.

Jonathan

[Nearholmer]

In the UK when one school insisted that children wear helmets it resulted in expelling some children.

Are you saying that a school expelled pupils for not wearing cycle helmets?

If that is what you are saying, I don’t believe a word of it.

[Steady rider]

Jdsk » 10 Jul 2022, 10:49pm

Steady rider wrote: ↑10 Jul 2022, 10:38pm
More data would be helpful.
You're right. But the problems with Clarke's paper aren't limited to there being inadequate data. The whole approach prevents any reliable inference about the effects of promotion on anything.

1 The Methods section doesn't say what was done. You've told us that some studies were selected and others rejected on subjective grounds but that no-one knows the criteria which were used. This approach is completely vulnerable to selection bias and confirmation bias.

2 There is no information on differences in promotion between the two countries, the key point under consideration.

3 There is no discussion of possible confounders.

Addressing each of these (and more) is essential to any observational study. And there are widely available guidelines available which should be used before publication and which would remove these basic problems.

Jonathan

I would disagree with the points made because there is evidence that Denmark took a different approach to the Netherlands and had a strong program of promoting helmets for children, http://www.copenhagenize.com/2008/08/he ... danes.html

It is known that helmet promotion can discourage cycling,

Cycling UK (2017) stated: However Cycling UK is not only concerned about the harmful effects of mandatory helmet use. By creating exaggerated perceptions of the risks of cycling, even voluntary helmet promotion campaigns have been found to deter some people from cycling.

The method used a practical approach to assess risk levels, showing how comparing helmeted to non-helmeted can include elements leading to an increased risk for non-helmeted of head injury, such as drinking. It provides details of the risk of helmet impacts and extra falls. It details the health benefits of cycling and issues with helmet promotion. It compares two major cycling countries, one that has strongly promoted helmets and the other without a strong program of promotion. The data provided shows NL increased their cycling levels by 19.4% v a decrease for DK of 15.4%. Information for DK shows cycling increasing in major city location and accident data shows a big reduction for children.

There is a link provided showing DK to have strongly promoted helmets and evidence quoted showing cycling reduced by 17% in one part and 15.4% as calculated.

There is currently no evidence to show any confounders are related to the changes reported.

The paper was limited to 12 pages, adding one extra sentence and one extra reference, would have exceeded to requirements for the submission. There was not space to add discussions on speculation about something with no evidence to support confounders or to provide an history of the NL and DK approach.

The points raised, listed 1 to 3, are of little actual value. If the paper was to be published, I expect the normal process may lead to some changes. Considering many young people in Denmark may now ride less because of helmet promotion it warrants close examination.

[Steady rider]

Nearholmer » 10 Jul 2022, 11:00pm

In the UK when one school insisted that children wear helmets it resulted in expelling some children.
Are you saying that a school expelled pupils for not wearing cycle helmets?

If that is what you are saying, I don’t believe a word of it.

The reference quoted was GMTV (1997), Expelled from school, Derby UK, reported 2 Dec 1997. Eamonn Holmes did the interview.

[Nearholmer]

Frankly, I still don’t believe it, and can only suggest that since 1997 the story has got muddled and inflated along the way. ‘Grown Whiskers’ I think might be the term.

Why don’t I believe it? Because having been a school governor for a while (oddly enough at about that time), I know that expulsions (‘exclusions’ formally, I think) are A Big Thing, and can only be made on very narrow and particular grounds.