If you want to see civil war break out in the cycling community, bring up the subject of helmets.
Yes, those polystyrene lids are a sure-fire way to stir up a frenzy on social media and in the comments sections of any website that dares bring it up. You might be thinking that we have some kind of masochistic streak to even mention it, but we think it is a subject that warrants some discussion.
There’s a tremendous body of evidence available, both for and against cycle helmets. On the one hand, providing that your helmet is fitted correctly and conforms to the standards set out for them, they may reduce injuries or the likelihood of a fatality in the event of an incident. However, this is a big ‘may’. Back in 1991, the magazine Which tested 18 helmets and found that 8 didn’t conform to the then current BS 6863:1989. We would like to think that things have improved since then, but it’s hard to be sure.
On the other hand, it is widely reported that in places with mandatory helmet laws, cycle use has a nasty habit of falling off a cliff.
In all countries where helmet laws have been introduced and enforced, there has been a substantial reduction in cycle use (BHRF, 1096). Helmet promotion has also been shown to reduce cycle use (BHRF, 1020). Cycling has substantial health benefits (BHRF, 1015) and people who cycle regularly live, on average, longer than non-cyclists with less illness and poor health (Andersen, Schnohr, Schroll and Hein, 2000). Concern has therefore been expressed that any benefit from helmet wearing is outweighed by the loss of health benefits to those deterred from cycling. This is particularly an issue at a time when reductions in cycle use and other physical activity have given rise to increased levels of obesity, especially among children.
Source: Contradictory evidence about the effectiveness of cycle helmets
So, you have to consider the risk of injury against a backdrop of increasing obesity, air pollution and congestion.
How helmets work…
In the event of an impact the expanded polystyrene balls in the shell of your helmet crush together, dissipating the force around your head. However, the balls don’t re-expand, so after an impact the helmet needs to be replaced.
This also means that in the event of an incident where the head sustains multiple blows, such as in a collision with a car where your head hits the bonnet of a car followed by the floor, you may well not be protected because the helmet was a spent force after the first blow.
Unrealistic Expectations?
These days our cycle helmets are designed to the EN 1078:2012 standard. Unfortunately, even if the helmet does meet this standard it still doesn’t mean a great deal. The standard is designed to protect you from linear accelerations but ignores rotational accelerations –so failing to unclip at the lights is probably ok, but being thrown into the air like a rag doll, not so much. Not only that, the standard doesn’t go as far as to suggest the helmet should protect you from a real incident, such as one involving a car.
Cycle helmets are specified by their manufacturers as meeting one or more of the international standards for this equipment. All of the standards test the helmet’s protection of only a decapitated headform, (i.e. one with no body attached); and all tests involve only low speed impacts. Impact speeds are less than 6.6 m/s (24 km/h or 15 mph), and in some cases, barely 5 m/s (18 km/h or 11 mph). Unlike seatbelt tests, helmet test standards do not realistically replicate serious crashes.
Source: Cycle helmets – an overview
Note that the test is on a decapitated headform, not one with a 70kg human attached as ballast.
There are helmets that conform to the superior Snell B90 or B95 standard, but these are slightly harder to find.
There’s a fairly comprehensive list of studies compiled by ROSPA here that you are welcome to wade through.
Even in the pro peloton where everyone is wearing a helmet –and a factory-fresh one at that, there are cases of concussion turning up from time to time.
On stage 5 of the 2011 Tour de France, Janez Brajkovic crashed and reportedly lost consciousness before being taken to hospital. Tom Boonen crashed on that stage too, but it was not until the morning before Stage 7 that he abandoned, telling Cycling News, “I think I have a concussion. I have a terrible headache. I was a danger to the other riders in the race”.
Source: Cycling and concussion: is it time to stop ignoring the dangers? | CyclingTips
Granted there’s likely to be a big difference in speed between someone riding the Tour de France and someone riding to work, but it does make you wonder.
Perception vs Reality
So, bicycle helmets arguably look safer than they really are, but what is curious is how motorists respond differently to someone wearing one, relative to someone without one.
Dr. Walker’s 2007 study used a bike equipped with a camera and a distance measuring device. He recorded data from 2,500 drivers who passed him on the roads close to his workplace, the University of Bath. Half the time he wore a bicycle helmet and half the time he didn’t. The results showed motorists tended to pass him more closely when he rode wearing a helmet. Such “punishment passes” can also lead to collisions, collisions which can result in injury and death – and not to those guilty of the dangerous overtakes.
Motorists Punish Helmet-Wearing Cyclists With Close Passes, Confirms Data Recrunch
So if you wear one, you may well experience more close passes and punishment passes than someone who doesn’t.
Weighing things up…
So, we know that helmets are bad for the uptake of cycling. We know that cycling is the solution to many of the ills facing society today, including social cohesion, obesity, air quality and inequality of opportunity.
Unfortunately, we also know that helmets are unlikely to protect you from a serious collision, but may reduce the severity of a minor crash at speeds barely above a standstill (forgetting to unclip as suggested above). We could generously estimate a 50/50 chance that a helmet may save your life whilst out on a ride, but if we also said that your chosen form of birth control was only 50% effective, would you still use it?
This is why this is such a divisive subject. It’s hard to argue that helmets are particularly effective, but it is also hard to argue that people shouldn’t wear one either. It is also frustratingly difficult to convince non-cyclists that the presence or lack of a helmet makes any material difference to the outcome of a collision –one of the main reasons we even thought to write this article. Simply not wearing one is often used as a get-out-of-jail-free card by anyone investigating an incident involving a cyclist.
If helmets were 100% effective and were light enough to wear all day, we would still have to deal with the public health consequences of a significant drop in cycling.
It’s a gamble, but it is one that people should be at liberty to make for themselves. On a population level the public health benefits to cycling far outweigh the consequences of a mercifully small number of people getting injured each year from not wearing a helmet that may not have protected them anyway.
Cardiff By Bike 