Brain injuries and the Dutch cyclist

An Australian reader pointed me at this document which is about head and brain injuries amongst Dutch cyclists. Yes, there are also some people in NL who think that helmets for cyclists are a good idea.

Rather than reacting emotionally we have to look at the numbers to make sense of this. The overall risk to Dutch cyclists (it's on page two of the document) of a "head/brain injury" is 153 per billion kilometres ridden. That means that one such injury is one per 6.5 million kilometres ridden.

On average, every Dutch person makes a trip by bicycle 5.6 times per week. This works out as an average across the whole population of 2.5 km cycled every day. That's the highest figure for any population in the world. If we assume that people cycle every day of their lives to the age of 80, and that they cycle that 2.5 km every day of their life, they will ride a bike for a total of 73000 km during their lifetime. Divide it into 6.5 million and you find a figure that a typical Dutch cyclist can expect a "head/brain injury" once every 90 lifetimes.

Note that it doesn't say how serious the injuries have to be in order to be included. However, it does give total numbers of head/brain injuries per year as 550 + 1600 = 2150 which is more than ten times the total deaths of cyclists per year from all types of injuries. For the sake of making the maths easy, let's lazily (and very inaccurately) assume that every death when cycling is due to a head injury. We then find that the risk of death due to head or brain injury when cycling is actually around once per 900 lifetimes.

Also, note that the article points out that cycle helmets can only reduce the rate of deaths due to head injuries by 29%. So, if a helmet is worn by that typical Dutch cyclist, it will save his/her life every 3100 lifetimes or so.

Death occurs once in every lifetime. i.e. Other causes of death are more than 3100 times so significant as deaths due to cycling without a helmet and that applies even in this country where there is more cycling than in any other. It applies even if for the sake of simplifying the calculation we make the horribly inaccurate assumption that cyclists never die of any type of injury. This in a country where 93% of the population rides a bike at least once a week.

To summarize, deaths due to head injuries while cycling are not a major public health issue and should not be treated as such. Helmets are not the answer to cyclist deaths. Good infrastructure is what makes cycling safer.

A contrast with another cause of death:

A couple of days ago I saw some other statistics, about a much more common cause of death and injury. This covered the risk of car crashes to Britain's children. In this post is the alarming statistic that one in 27 children in Britain, more than one in every classroom, can be expected to be killed or injured in a road crash by the time they are 16.

Think about it. If the risk is similar in other age groups, then there is a chance of one in five that you will be injured or killed in a road crash during your lifetime. That's a risk due to motor vehicles which is many times greater than that faced by cyclists in the Netherlands not wearing a helmet.

Britain's roads are actually amongst the safest in the world, for drivers. However the risk of death or serious injury from road crashes elsewhere is higher in every other country than this one, where there are more cyclists than in any other country.

Previously I covered the efforts that car manufacturers have put in to make driving appear safe.

Also... 2.5 km per day may not sound much, but this is the highest average cycling per day per person figure for any country in the world. It's the average distance cycled for absolutely everyone, all age groups, through the entire year, averaged across an entire lifetime. By comparison, English speaking countries all hover around 0.1 km per day by bike per person (look it up if you don't believe me). In all places, keen cyclists of course cycle a lot more than the average. Long distance journeys by bike are also more common in the Netherlands than in any other country.

(and no, we don't sell helmets...)

"This must never happen again" - how did 1.2 million deaths a year become normal ?

"Victim blaming" started
quite early on as this article
from 1929 illustrates

According to the World Health Organisation, the coroner who looked into the world's first car crash fatality, back in 1896, said "This must never happen again".

Unfortunately, it did happen again and it's kept happening ever since. These days, there are 1.2 million people killed every year by car crashes and another 50 million injured. If road deaths continue to grow at the expected rate, it is estimated that we will have seen growth of more than 60% between 2000 and 2020, meaning that nearly 2 million people per year will lose their lives in car crashes by that time.

Who gets hurt ?
"Most of these injuries will occur in developing countries where more and more people are using motorized transport. In these countries, cyclists, motorcyclists, users of public transport, and pedestrians are especially vulnerable to road traffic injuries."

In total, motor vehicles have killed more people in the last hundred years than wars have (I mentioned this in a previous post, but it bears repeating). Yes, motor vehicles have been far more lethal than such things as nuclear weapons, machine guns and napalm. In fact, you can add up all of the damage done by those things, and all the results of all terrorism right across the world, and still come up short of the death toll due to motor vehicles.

Crashes surprise people
Why do we put up with this ? I have a theory. I've noticed that while the lethality of motor vehicles might seem obvious given the results, people are often very surprised when cars crash and the results are serious. Cars feel safe and they are marketed as being safe but the danger that they present is beyond what people realise.

An Atomic Bomb. Not nearly so
deadly as automobiles.

If we fall when walking, the magnitude of the injury is quite close to what people expect. Normally you'll do no harm at all or perhaps get a minor injury such as a sprained ankle or scraped knee. You can go faster if you run, but you get worn out quickly.

Cycling is a little more unpredictable. We've used a machine to make ourselves faster, but it still takes considerable human effort to raise our speeds much (there's a calculator here which shows how much effort for different speeds). Higher speeds are possible only after you've cycled enough to build the muscles, and experience comes at the same time. Falls hurt much more if you're going faster. If we fall while descending a hill the crash can be particularly dangerous. However, at least when you cycle you know it's going to hurt if you fall off. Personally, I like riding fast, but I'm a timid descender of hills because when going down hills some of my control is taken away.

Cars give another considerable increase in speed, and there is a further difference. You can go fast for no real effort and with no practice or skill required. What's more, cars remove the cues that normally make us realize we're travelling fast, such as wind noise, and the feeling of wind in the hair and on the face.

While even "slow" speeds by car are quite dangerous (especially for people outside the car), driving feels safe. It's so sanitised an experience that it's actually boring enough for people to fall asleep while driving at speeds which would keep you very much awake on a bicycle.

This is why crashes are such a surprise. People often simply don't know what happened when they crashed a car. People stop concentrating on what they see as mundane tasks and that's why no amount of legislation will make drivers safe.

Somewhere in middle of the confusion comes the blame shifting. If you walk into someone in the street you would not blame the other person. If you cycle into someone you also probably wouldn't. However, driving somehow changes this. The victims frequently get the blame.

How to solve the problem
There is a simple way to solve this problem of vulnerable people being hurt and that is to remove the cause of danger from where the vulnerable people are. Where cyclists are concerned, cycle-paths are the most obvious way of achieving this. It is also possible to remove danger by unravelling driving routes away from cycling routes and to otherwise segregate modes without building specific cycling infrastructure. Places for people who don't drive, such as schools, should not be designed around cars. City centres should be accessible without the threat of danger.

When conflict and risk are designed out of roads by following the principles of sustainable safety, the injury rates drop.

The result of separating motorists from cyclists and pedestrians: Between 1972 and 2013, fatalities on Dutch roads dropped dramatically. Child fatalities reduced to just 2% of their former level.

It's not a problem for society if those who are looking for a thrill in a car do so on closed circuits but it is if they do it on the public roads. Many people claim that they like cars and like driving but very few take up motor sport so they can truly test their skills. In reality the purported love of driving often comes down to nothing more than people driving cars to get to places because it is the least bad option open to them.

1.2 million deaths per year are tragic enough, but they're actually just the tip of the ice-berg. There are also 50 million people injured each year by cars. What's more, the deaths due to crashes are not all of the deaths. It is difficult to pin down exactly, but some estimates put deaths due to pollution from cars at ten times the figures for crashes and deaths due to effects such as obesity due to a sedentary lifestyle assisted by the car are also a major cause of death.

The image at the top left comes from the December 1929 issue of Popular Mechanics magazine. Exactly the same policies, of shifting blame onto pedestrians for being hit by cars, exist all around the world, including in current safety campaigns in the UK.