[SystemSafety] Bicycle Helmets

[Les Chambers]

Hi All

A case study: 
About 20 years ago I misjudged a detour around a woman walking a dog in a local park. I was focusing on not getting my wheel caught in the gap between the grass and the concrete path when I looked up and saw I was heading for a cliff. Any mountain biker knows that you need to focus about 20 metres ahead because what's right in front of you is just about to happen and it's totally out of your control. So it was with me. I sailed over the cliff, was propelled through the air and attempted to head-butt the planet earth out of my way. Two things saved me from serious injury. Firstly I was wearing a bike helmet and secondly my body was being propelled forward. The impact on my head was not straight down but at an angle. Most of the force was taken by my shoulder, crushing my AC joint, then the rest of my body which had all its muscles wrenched. I lay on the ground in the most incredible pain. Pain I thought not possible to endure. Then the lady with the dog came over to render assistance. Of course there was nothing to do (most people don't arm themselves with painkillers for a walk in the park) but she did her best focusing on stroking my arm. I remember thinking, "I wish you would stop that lady it's not helping," but I didn't want to offend her, I knew she was trying. Then her dog started growling at me. I remember thinking,"... not a very successful morning, knocked senseless in a park then savaged by an Alsatian." 
So I lay in the park with no position I could take that would stop the pain, looking forward to the arrival of the ambulance. By this time a crowd had gathered and I whispered to somebody that my mother-in-law lived on the other side of the park. She was of the hardy generation that had endured World War II. Her husband was absent the entire time flying Sunderland flying boats on submarine patrols in the English Channel. Shooting it out with German night fighters and submarines that surfaced and took them on. I knew she'd be less shocked than my wife  ... better able to break the news. At this point I didn't know how tragic this incident would turn out to be. But at least my brain was working and I could feel my toes. 
An ambulance arrived and they gave me something shaped like a whistle. You could regulate the painkiller by putting your finger over an air intake. I took it to the max. "How good is this," I thought. Less than 20 minute response time and drugs. Drugs are great! Painkillers to " ... knit up the ravel'd sleave of care; The death of each day's life, sore labor's bath ..."
The ambulance had a boy/girl crew. The closest point of access to the accident site was a bridge about 30 feet above where I was lying. There was a very steep set of steps up to the roadway. To get me up the steps without pitching me out of the stretcher required one ambulance person to hold the stretcher above his/her head and the other to stoop down low. It turned out the girl didn't have the strength. So they called another ambulance to get another boy. "Even better," thought I, now floating on a glorious drug induced cloud. Having lived in foreign countries where the afflicted were just a nuisance, where they were more likely to move your carcass to the side of the road like a dead possum and have your family come and get you - I fully appreciated the service.
When they got me to emergency my wife magically appeared and held my hand for three hours. I can't emphasise enough how comforting that was - combined with a good shot of morphine. Morphine is so good! 
Around midday the morphine began to wear off. I put up my hand and begged for more. They said, "No." I said, "What!"
They said, "We'll give you aspirin." I said, "You're kidding me!" Then they said, "You can go now." Evidently they'd figured out I had not had a heart attack, I'd only busted and A/C joint and sustained some bruising and muscle strain. A low-grade football style injury, too trivial for an emergency department, not worthy of keeping me in even overnight, certainly not worthy of more morphine. It's a great weight off your shoulders when they tell you you're not sick - apparently. I got up and walked out. 
It took me about two months to recover from that one. I'm self-employed so I was at my desk the next day developing a training course on writing software requirements. I discovered an interesting phenomenon. When your body suffers trauma your mind just shuts it down and focuses on the essentials. For me it was avoiding commercial oblivion. I had a client expecting me to turn up within the month with a training program. I've never been so focused and calm in my life.

So, to cut this long story short I feel I am alive and functioning today because of my bike helmet. I just do not believe my naked head could have survived the crushing blow it took when I hit planet Earth and it refused to wobble out of orbit. 
Today I still cycle 100-200 kilometres a week and socialise with a very large community of cyclists, some of them retired professionals from the European racing circuit. Many of them, like me, would say they are still alive today because of their helmets. We are collectively amused at this thing we often see in Brisbane. Maybe it's an Australian thing. Some cyclists have this weird habit of riding down the road with their bike helmet hanging off the handlebars.

This is our collective definition of an idiot!!!

Cheers
Les

PS: Analyse that Nancy.


-----Original Message-----
From: systemsafety-bounces at lists.techfak.uni-bielefeld.de [mailto:systemsafety-bounces at lists.techfak.uni-bielefeld.de] On Behalf Of Peter Bernard Ladkin
Sent: Monday, October 13, 2014 9:40 PM
To: Messer Robin; DREW Rae
Cc: The System Safety List
Subject: Re: [SystemSafety] Bicycle Helmets



On 2014-10-13 11:02 , Messer Robin wrote:
[Drew Rae] There's a severity filter in that accidents below a certain threshhold don't get
reported. I think
> this is what is happening in the British study -  if you define the size of the accident by the size
> of the injury, then of course the same sized accidents have the same sized injury regardless of
> whether you are wearing a helmet.

And there is a phenomenon at the other end. A bike helmet won't protect much at all in heavy
collisions, in which the cyclist is hit hard. So for these sorts of collision, the numbers are going
to be about the same.

Also amongst the confounding factors are the exigencies of reporting overdetermined fatalities, in
which a cyclist suffers many injuries, each one sufficient to cause death. But one cause is given.

Indeed, it surprised me that the results suggested that, in a range of accidents of which a fifth
were fatal, over half of those fifth (that is, over a tenth) were accidents in which head injury was
a cause of death and also (asserted to be) preventable by a helmet. Taken literally, the spokesman
is suggesting that one in ten moderate bicycle accidents are such that a life is/would be saved by a
helmet, as well as just under one in ten in which it wouldn't be. Those are very different kinds of
figures from those I recall. I have to revisit (but not until I've finished my current task!).

[Robin Messer] I have been in one significant cycling accident (in about 30 years of regular
> cycling). My helmet took a bashing ........ I couldn’t
> bring myself to report the accident./*

Good, thanks. A concrete example of the phenomenon Drew describes. Also very good that you weren't
badly hurt!

[Drew Rae] Helmets, unfortunately, are purely a severity reduction (or more precisely, reduction in
likelihood
> of the worst severities). They don't do anything to prevent the accident, which can be pretty bad
> even with a helmet. I've just moved back to the big city and I'm seriously considering changing my
> cycling habits.

Understandable. Also the environment is very variable by country (visit any Dutch city!). See below
for some phenomena that are likely not well known.

> */[Robin Messer] There is evidence to suggest that wearing a helmet actually increases the
> likelihood of the accident occurring. http://news.bbc.co.uk/1/hi/england/somerset/5334208.stm/*

Yes, I remember we all discussed Ian Walker's work. I hadn't realised it was so long ago! He also
gained a tenth extra space by wearing a long-haired wig...... Since we discussed it, there is a
paper made available on the Uni Bath WWW site: http://opus.bath.ac.uk/37890/1/Walker_2013.pdf

He measured mean separations which would be illegal in Germany. 133cm in 2007 and 117.5 in the more
recent study. The German traffic law says 2m. There is long-standing case law which determined that
1.5m is too little separation in the case of an accident (that is, the overtaking vehicle was held
to be fully or partially at fault, having passed at approximately this distance), but our local
police stated their intention to try a campaign to get people to pass at 1.5m, suggesting that they
know perfectly well that many drivers don't give this amount. In my experience, something over three
quarters of overtakers give me this room, but equally there is a significant, continual minority
which don't. There is also a law which says that bicycles must be ridden within one meter of the
(defined) edge of the road. The local (volunteer-run) vehicle safety bureau recommends staying just
under this amount, but in any case always more than half a meter away from the road edge, which is
not necessarily the same as the curb. If one rides one meter away from the road edge, there is at
least another half meter of body+handlebars sticking out and some substantial minority of drivers
are inclined to become at least impatient and sometimes aggressive (which, BTW, violates explicitly
the main traffic law in Germany, which is to act always with due care and attention to the safety of
other road users. And that means without qualification: no matter what they are doing or what you
think about it!).

Tim Schürmann of my group just advised me of a recent court decision, in which liability for an
accident was apportioned. First, some blurb about the legal situation here. Most of German traffic
regulation and traffic law concerns apportioning liability. This seems odd to people used to UK or
US law: although it appears to specify how you should drive/ride, it really means how you should
have driven/ridden beforehand if an accident has occurred, in other words there has been no offence
without an accident. There are some exceptions: breaking speed limits is one which is an offence in
itself. I think driving/riding through stop signs and red traffic lights are others. But there are
legal tricks to achieve conformance even without an accident. If a policeman stops you for riding
your bike on the "wrong side" of the road on a bicycle path, there has been no offence because there
has been no accident. But heshe charges you a fee of, say, €20 for "(legal) instruction" (Belehrung)
concerning your riding habits.

The court decision of which Tim informs me is quite recent: 17 June, 2014. It is at
http://openjur.de/u/701359.html in German. It concerns apportionment of liability (of course) for an
accident which happened in 2011. Should the cyclist assume some liability? She was not wearing a
helmet. The court said it would suffice for joint liability if wearing a helmet for self-protection
was deemed to be part of general cycling knowledge/good practice at the time of the accident. The
court decided that indeed it was/is.

To me, this is quite tendentious terrain. It can also considered to be good practice/common
knowledge that clothing protects you from gravel rash and in some cases from impact. By "protect" I
mean reducing the severity. Does that mean that riding in short-sleeved shirts and shorts makes one
jointly liable for injuries sustained in a collision solely caused by someone else? Competitive
in-line skaters around here don't wear elbow or knee protection, although they usually wear helmets.
Hobby in-liners usually do, for obvious reasons. Does that mean joint liability when a training
skater is hit by a vehicle whose behavior solely caused the collision?

This decision came from the State Appeals Court in Schleswig-Holstein, so it is the highest instance
available in that State, except for the Federal Constitutional Court. I don't know whether there is
a constitutional issue that could be contended. Also, I understand that other states are not
necessarily bound by the decision, although the reasoning will surely be taken into account
throughout the Federation.

Also, I doubt whether such decisions will affect a personal decision to wear a helmet. Those who
choose not to wear a helmet are evidently supposing they will not be involved in an accident. So one
imagines that a different apportioning of liability in case of accident will be equally discounted.
On the other hand, such rationality is not necessarily to be assumed (thank you, Professors Kahneman
and Tversky).

PBL


Prof. Peter Bernard Ladkin, Faculty of Technology, University of Bielefeld, 33594 Bielefeld, Germany
Tel+msg +49 (0)521 880 7319  www.rvs.uni-bielefeld.de




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