In order to show that helmets *cause* accidents, they need to create a randomized study where they force employees to flip a coin to decide whether to wear a helmet or not.
Otherwise, here's one plausible scenario: Employees who work in tiny suburbs with small roads and very little traffic feel safer, and this are less likely to wear a helmet. They get in less crashes because their town has fewer and safer drivers. Employees working in the city have more crashes simply because of being in a busy city, so they are more likely to wear helmets.
Right now, you cannot prove that helmets cause crashes and not the above.
In reality there are confounds both directions. The effects of helmet wearing are higly contingent based on the geography and demographics.
Here is a review (from just 3 years ago) of such studies:
https://www.sciencedirect.com/science/article/pii/S136984781...
> Risk compensation, as it is typically defined and understood, is only one of six possible scenarios, namely a usual non-helmet wearer puts on a helmet and increases their risk taking. Importantly, evidence in the opposite direction, i.e., taking a helmet off leads to less risky behaviour, is not evidence in support of risk compensation as it is a type of logical fallacy
After reviewing that article none of the studies are convincing either way. The only studies that actually look for causality are the ones which only measure speed to asses risk. Those are also the one that I would qualify as positive results but were listed as negative results because of that above mentioned logical fallacy.
So while is is possible to untangle these effects, it has yet to be done properly to show a clear result either way.
Research on helmets has been ongoing for 40 years, and has even led to ANSI standards for helmet design and protection. The UCI requires hemets in amateur and professional events. This isn't about risk taking behavior, it is simply about if you do have an accident, you won't be killed, turned into a vegetable or concussed when you hit your head.
> The effects of helmet wearing are higly contingent based on the geography and demographics.
I'm pretty sure that hitting your head on Ugandan cement will damage your head roughly the same as American Cement or European cement. S
Additionally, I've never seen any research showing any kind of demographic relationship to severity of head injuries in bicycle accidents. Nor have I once saw research that did anything other than present some statistical noise about distance cars give you based on helmet or not. Close shaves are not accidents or injuries, so even the basis of the research is questionable.
The effects of a helmet on overall safety when ridden at low speed on dedicated bike paths is very different from when ridden at high speeds in traffic with no bike lane.
Thus the the design of the city and streets (geography is perhaps not the perfect term for this) and the what/how of the local culture's bike riding behavior (perhaps demographics is a bad term for this, not sure of a better one.) have huge impacts on how much a helmet affects your safety simply because the risk profiles are very different.
The data is messy due to regional variability plus the difficulty of reliably removing the confounds mentioned above. I would never discourage someone from wearing and will actively encourage it when riding in bicycle hostile areas. At the same time, I think the push for helmet laws and helmet education is often a cop out to avoid talking about how we need to redesign cities to support safe bicycling. If we did the later, we would see much larger safety gains and the former would be much less necessary.
Oh I'm so tired of this meme!
Plenty of times causation is found through correlation. Plenty. Of. Times.
Cars already have airbags and seatbelts which help a lot for the kind of collisions that would otherwise result in head injuries.
> It might make you much safer in case of a crash, according to your reasoning.
I don't see what in their comment could be construed to say that helmets make you much safer regardless of vehicle.
> Wearing a helmet can itself become a leading factor to cause an incident
Is there a source for this? Should be a randomized A/B test as you mentioned, not just a correlation - wearing a hi-vis jacket or other precautions taken more often in dangerous situations probably also correlate with accidents.
Even if helmets do cause accidents through increased carelessness, some may still take issue to intentionally making a scenario more dangerous such that people are more careful. It's kind of settling for a local minimum, rather than aiming to reduce inherent risk alongside aligning people's risk estimates to not overestimate the precautions.
A competent car helmet is probably a motorcycle helmet, which is more like $100 to start, but it impacts hearing, reduces vision in all directions, is a significant weight, usually doesn't adjust much for sizing, takes longer to put on (especially if you wear eyeglasses).
A bike helmet in a car would likely be more trouble than anything, it would interfere with the headrests and probably increase neck injuries.
Your "simple equation" relies on your variables being solid. And they aren't.
It's important to stress that the behavioural studies from Bath (that show helmeted riders take more risks in simulations, that cars give them less space) are not data about whether helmeted users are at greater risk. Or that comparisons between US and NZ riders and outcomes are comparable because of vastly different road and rider profiles.
It's also hard to show how much helmets are helping because zero-harm accidents are rarely reported, so if we assume that they function correctly, and do reduce harm in impacts, we simply don't know how many near-misses there are.
You can look at hospital admission data two studies show 75 and 78% of cyclists admitted with serious-enough head/neck injuries hadn't worn a helmet. That still needs adjusting for total accidents, and proportion of helmeted riders on the road in the first place. Again, poor reporting makes this tough.
You also have to be aware that some studies and stats are polished up by people fervently for and against mandatory helmet laws. Biased reporting doesn't help anyone. There's a good selection here: https://www.helmets.org/stats.htm (domain suggests a strong bias, but I'm not sure).
Pedal Me doesn't provide a good argument here. It seems more like they're worried what their customers will think (do they need helmets too?) and nothing to do with actual safety outcomes.
American Football vs Rugby and the difference in CTE is often cited as the prime example of where this is true. Helmets and shoulder pads encourage riskier hits.
I think a lot of people —including experienced cyclists— would be surprised how easily a silly little fall, a knock against a car, can just kill you.
So even if a helmet makes you marginally more likely to be involved in an accident, being a professional vulnerable road user, all day is no joke. I'd like to have safety equipment when my number comes up.
American Football is all about set plays. You line up and then charge at each other, meaning you have two lines effectively charging at each other and can focus all your effort on this one effort.
Rugby is much more fluid, so the amount of direct head-on-head collisions is much lower, and the distance someone typically runs before tackling someone is much lower as the 'engagements' are more frequent.
American Football is like going from 0-60mph every 10 minutes, whereas rugby is about sitting at 30mph constantly.
I agree linemen are a novel concept, but they’re not the only victims.
Combine that with the fact when a Rugby player makes an extended run, they aren't often tackled directly head or side-on, it's more perhaps an "anchor" tackle from the back to pull them down. In american football, the safeties and deep players have more opportunity to get head-on with a receiver while the ball is in flight, while a rugby full-back having to watch and run horizontally while the player is running means they are less likely to be directly head-on.
Further combine that with the fact that Rugby governing bodies have penalised 'high tackles', and the rate of CTE drops significalty.
Is your core argument that rugby is safer because the players are more tired at any given point so they don't hit as hard? Other than that, I am struggling to figure out the mechanism between stopping more frequently and football being more dangerous.
>Combine that with the fact when a Rugby player makes an extended run, they aren't often tackled directly head or side-on, it's more perhaps an "anchor" tackle from the back to pull them down. In american football, the safeties and deep players have more opportunity to get head-on with a receiver while the ball is in flight, while a rugby full-back having to watch and run horizontally while the player is running means they are less likely to be directly head-on.
I'd suggest you watch videos like [0] to diligence your claim that head-on tackles aren't common in rugby.
The nuance that you are missing is the power equation - American football's best tacklers focus on short-duration, high-work contact (i.e. maximizing power) to knock an offensive player off their feet [1]. Think of it like placing a nail. You can swing a metal hammer and a rubber mallet (of the same mass) against the same nail and the metal hammer will always drive it better because the dt portion of the power equation (i.e. the denominator) is smaller.
The metaphor extends: rugby players may put in the same amount of work (or more!) on a given tackle, but the dt part of their power equation is much higher than in the NFL because humans are squishy (in practice this is also why you see so much more form tackling in rugby - it's hard to generate enough power to just knock someone over without wearing pads).
Ultimately, high power hits are what cause the rapid, high energy head movements that cause CTE and those are just easier to do in pads.
[0]https://www.youtube.com/watch?v=ZOFO_MzZi50 [1]https://www.youtube.com/watch?v=r3Bh9LHMEeY
Because I have a seatbelt, an airbag, and a reinforced shock absorbing shell around me.
I'm not going multiples of walking speed on something standing upright only thanks to gyroscopic forces, so no.
Also even when running I have way better maneuverability than as a cyclist.
Generally limbs > wheels when it comes to getting out of trouble.
I wear a helmet when skiing though.
My car has other safety measures in place to protect me from head injuries. A bicycle does not.
Would it? I've never heard anyone recommend this, but if this did actually reduce the likelihood of a serious head injury in the event of a car crash, then I would seriously consider wearing a helmet while I drive a car. I have no problem wearing one while I ride a bicycle or motorbike.
I am not aware of any studies looking specifically at the effects of helmet wearing on TBI rates of regular drivers, but then good data on that for bicycles is also hard to come by but that doesn't stop people from pushing for bicycle helmets.
Yet, lethal TBIs are more likely to come from motor vehicle accidents than from bicycle accidents.
> the risks seem low enough that the expense (including time to equip) of that additional equipment is too much to justify its general use.
Yet, somehow this argument is deemed irrelevant when helmets for bicycles are discussed.
There really is not a compelling reason why helmet usage in a car is different from on a bicycle. The main difference is social acceptability, not any objective risk analysis.
Is that per mile, per minute, or per lethal TBI? Also, is a collision between a bicycle and a motor vehicle a motor vehicle accident or a bicycle accident?
Of course, bike helmets protect against more than just brain injury. They also protect against road abrasion of some portion of the head, which is not usually a factor for car occupants, except if they're ejected or they're in a car that rolls over and doesn't have an roof or an effective roll bar.
Bike helmets are much lower expense and hassle than car helmets (which are mostly motorcycle helmets) and neck restraints, etc. If it's a public use bike system, especially the leave anywhere bikes, the expense and hassle gets overwelming, and helmets for customers of a pedal cab would be similar.
I've got a bike helmet with integrated lighting, which adds functionality and is kind of neat, although it was much more expensive than a good enough helmet.
Per lethal TBI, I don't think the data exists for per mile or per minute.
> Also, is a collision between a bicycle and a motor vehicle a motor vehicle accident or a bicycle accident?
Good catch, looking at their methods, they do include IDC-10 codes for pedestrian and bicyclist injuries due to motor vehicles in that number so I am not sure how many of those are actual vehicle occupants and I can't find any data at the moment that breaks those numbers down per IDC code group.
> Bike helmets are much lower expense and hassle than car helmets (which are mostly motorcycle helmets) and neck restraints,
I don't know, however, if a helmet may work worse in conjuction with an airbag though. So personally I think I'd stay away from helmets in cars (but I really have too little data to make an informed decision).
Having said that, in the case of this company, perhaps they could offer their passengers a "Hövding" device? (Hövding being the swedish word for a chieftain, but "hövve" is also slang for head, and in the case of this product it is a... "backpack/necklace thingy" that is a wearable airbag. Supposedly works really well, but probably comes with a price tag matching this function.
Whether I do or not has a lot to do with how likely it is that I might get in an accident. Wild right? Why would I opt for more safety gear in a more dangerous situation.
But besides that, even if the average nation-wide number of accidents can be taken as a basis for nation-wide policy making because confounders can be ignored (a huge assumption), you can still not use this data reliably for individual decision making or policy making for smaller groups without further analysis. You need to account the variance, where the confounders occur, and what these confounding factors are. For example, regarding individual decision making, it could be the case that certain people who cycle with helmets on the average cycle more recklessly, but you cycle even more carefully with a helmet and are better protected. If so, you cannot take the average to inform your cycling. The same holds for other groups, such as professional cyclists for a company like in this article.
To give another example, consider accident statistics of self-driving cars versus human drivers nationwide. The human driver statistics include each and every reckless and drunk driver in the country, including many people with whom you'd never share a car ride. At the same time, you might have been driving accident-free for more than 40 years. For you personally, or a specific group you belong to, self-driving cars could thus be way more dangerous than driving yourself.
Some of this difference is due to the innate and insidious sense of invulnerability with protective gear. It comes naturally even the first time you don it. It's a common source of accidents and something that must be trained out of you.
Being able to get back up unscathed from bad falls also reinforces your future confidence, or lack thereof, which I can also attest from having fallen many times both with and without protective gear.
I'd still never ride without (at least) a standard helmet. If helmets do factually cause more accidents, which is plausible for the reasons I just mentioned, I'd support making helmets mandatory for employees through legislation. It doesn't matter if the numbers support the opposite conclusion: maximizing individual safety in the eventuality of a crash is paramount. If you have ever had a head impact while wearing a helmet, you will understand why.
Do you wear a helmet when you drive inside your car? If not, why not? It might make you much safer in case of a crash, according to your reasoning.
Wearing a helmet can itself become a leading factor to cause an incident, and it's clearly what they are hinting at in the linked article: that data seems to indicate that riders wearing helmets may be getting more incidents on average. Then it's a simple equation: number of incidents x gravity of the incident in both A/B scenarios, and compare which one is the most favorable. It's not a question you answer with a "what the actual fuck" kind of reasoning.