[SystemSafety] Royal College of Paediatrics weighs in
les at chambers.com.au
Thu Nov 20 00:42:06 CET 2014
Drilling down on your risk reduction strategies - two points: shinning down
a rope and walking in the United States of America.
1. The rope. You have a rope and an anchor point but how do you plan to
attach the rope to the anchor point (it's a single point of failure). Do you
plan to use a knot or some pre-configured rope snap or clip. If you plan to
use a knot what is your compliance level? For example: Are you certified for
tying defect free bowlines blindfolded, in a mental state of fear and panic,
surrounded by smoke and flames. Then there's the issue of rappelling. A
nontrivial task. I would recommend adding rope shunts and safety harnesses
or other rope rappelling gear to your kit. Further, I recommend you
recertify as soon as possible. Find a burning building and test your skills
descending a rope while being hosed down by firemen in the presence of smoke
and flames and lashings of fear. Five years is sufficient time to have rope
fitness melt away. Just the ageing process plays havoc with simple things
like balance. I had this proved to me in spades on a recent Atlantic
crossing. Being a keen cyclist I thought my balance would be good but
discovered this was not so. Try closing your eyes and standing on one leg.
Alternatively practice base jumping and substitute your rope for a
2. Walking. Having lived in the Bay Area in a previous life I can confirm
you have violated one of the basic safety rules of California living. DO NOT
GET OUT OF YOUR CAR. I discovered last year that this rule also applies in
Miami. On a one-day stopover I hired a limo driver to give me a "cultural
tour". All over the world Limo drivers are a mine of information, not only
on the local colour but also they have marvellous stories to tell about
their lives. This guy was a Cuban refugee. We passed through a rough
neighbourhood and saw a man standing in the street looking at a block of
land. He was of Japanese appearance. "I hope he knows kung fu." Said the
driver. Yet another risk management strategy.
Hope this helps.
Seriously though, the rope tying metaphor can be useful in engaging people
with the extent to which their every-day safety depends on others. In safety
training environments I ask people to look around them and identify someone
who has shoelaces. When I get a show of hands I pick one and ask this person
how much they care about how well the shoelace owner ties knots? I always
get a quizzical look. Then I relate the story of the burning building, the
rope and the anchor point. The shoelace owner ties the knot then says, "You
first. I'll be right behind you."
"Now do you care?" I ask.
Given the extremely low probability that an individual will ever experience
the burning building scenario, the only way to raise safety awareness (and
to make some preparation for the unthinkable event) is to tell them a
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: Wednesday, November 19, 2014 4:19 PM
To: The System Safety List
Subject: [SystemSafety] Royal College of Paediatrics weighs in
Continuing our critically acclaimed series concerning Guardian outtakes on
UK child road safety:
Some numbers jump out. 25 children died as pedestrians in urban areas in
2011, compared with 311
adults. So child-urban-pedestrian deaths are (were in 2011) less than 1% of
road deaths overall in
the UK. Some observations:
* The RCP is actually asking for a whole package of measures. There are 2000
child deaths per year
in the UK and they want to reduce that number. Urban road unsafety accounts
for just 1.2% of that.
* The general "risk pyramid" for road unsafety in the UK has factors of
around 10. That suggests
round 250 severely injured and 2500 lightly injured children, if the
uniformity implied by the risk
pyramid carries through to specific categories (for which I have no evidence
one way or the other).
* If we are talking around three thousand injured children per year in urban
road accidents, that
does suggest to me that measures might be worth implementing, on the basis
that simply exhorting the
kids to be more careful is unlikely to affect behavior or outcomes much. I
would have thought
adducing those overall figures would have had more impact than just adducing
the small number of deaths.
* Does anyone know what physical basis the "collisions at 20mph" /
"collisions at 30mph" etc figures
have? Being hit by a car *initially travelling at 30mph* is of course
different from a collision at
a closing speed of 30mph. Also, many collisions with an initial closing
speed of 30mph would simply
not take place if the initial closing speed had been 20mph. The dynamics of
the interaction must be
The dynamics of a typical collision are
1. Perception by one or more participants of a space conflict, an imminent
collision (stages PA,
Perception and Attention, of a PARDIA sequence. "Perception" refers to
circumstances being presented
to a sensory field; "Attention" to them being cognitively registered.
Informal use of the word
"perception" commonly refers to both stages, but we found it appropriate to
separate them for
2. Latency between perception and action (representing RD: Reason and
Decision; the cognitive
formulation of a course of action). In an unanticipated situation, this
commonly takes between 1 and
2 seconds. (German traffic law says "1 second". In keeping with Napoleanic
law, it is normalised,
and as so often the normalisation of the phenomenon is not bound well to the
3. The decision made on the action. For a more-than-two wheeled-vehicle
operator, usually some
combination of swerve; brake; do nothing. For a two-wheeler, including
bicycles, add lay-down.
4. The executed action (here the IA parts together: Intention and Action.
They are separated in
PARDIA primarily to account for the phenomena in GLOC incidents, which don't
occur in road traffic).
Relatively few collisions occur without a progression through these stages.
The stage 4 events
change the dynamics of the collision: the incidence of the trajectories and
the relative velocity.
And of course it is the dynamics of the collision which largely determine
the damage, along with the
3D spatial configuration of the participant objects. These causal factors
are constrained by the
initial conditions (trajectories before the PA of PARDIA; 3D spatial
configuration of participants)
but I would propose that the initial constraints are not as determinant of
outcome as traditional
approaches to road safety suggest.
In 2011, I considered motorway Auffuhr accidents, which have been occurring
thankfully rarely) on motorways/freeways/autobahnen in Western Europe and
the USA for at least 60
years, and are usually put down somehow to irresponsible driving behavior.
They are in fact system
phenomena and this is easy to show: they result from rational decision
making on the part of
multiple operator/participants with limited mutual communication - and a
relatively rare property of
the environment. Indeed, I imagine similar conditions, decision making and
behavior occur far more
regularly than the accidents. The crucial difference is the relatively rare
Nevertheless, we may expect the accidents to carry on happening and the
police and judicial
authorities in some countries continuing to seek out participants to blame.
Yet systems analysis
shows this is a fundamentally mistaken approach. Systems analysis is a
foreign discipline to
professionals in road safety. We could change that.
In 2012, I performed a qualitative systems analysis of same-direction
spatial conflicts. It took me
at least a week just to derive an appropriate ontology. For example, it
turns out that one doesn't
need 2D-continual trajectories. It suffices for the decision-theoretic
analysis to consider
trajectories akin to specific configurations of railway tracks. The analysis
gets quite complicated
(I didn't spend enough time to make it simpler) and remains incomplete. I
should really get around
to finishing it.
Unlike some here, I regard road safety as the most pressing system safety
issue most of us
encounter. There are system-safety issues with living in buildings, but
these at least in Germany
are a tenth of the size - about 600 people die in building fires in Germany
each year; 5000 or so
die on the roads.
(Apropos indirect-electrical-safety: about a third of fatal building fires
are solely caused by
electrical faults. Let's say that's 600/3= 200 deaths. Whereas only 15 or so
people die each year
directly from electrocution. So the real electrical-safety issue lies in
arc-fault detection in building circuits. The detectors do exist, thanks to
which I looked at a decade ago, but an arc-fault-detection/protection device
costs upwards of ten
times the price of the usual Class A residual-current + short-circuit +
which costs a tenth of the price. Nevertheless, I am thinking of spending
the thousand or couple
thousand euros it would cost to equip all my building circuits with
I do have pervasive smoke detection, and a climbing rope and good anchor on
the top floor with the
bedrooms. I did check I can still rappel half a decade ago. But I don't
insist that visitors
can....... The social cost-benefit analysis doesn't yet work for regulation:
VSL is way lower. But
*my* life is worth way more to me than VSL.)
I should note, apropos some recent comments here, that many road safety
issues are country-specific.
For example, the single most prominent factor in rural bike-car collisions
in Germany is a specific
roadway configuration which doesn't exist in the UK. Also, there are many
conflicts in Germany from the provision of cycle paths on the sidewalks.
That doesn't occur in the
UK either. Or in the Netherlands, where city cycle paths are separated from
pedestrians, and often
from the motorised-traffic roadway. Many pedestrians, even those who have
grown up with the system,
wander all over the German urban cycleways without looking. Some cities,
such as Bielefeld, are
coming slowly to realise the consequences of requiring cycle paths be used
(namely, the city assumes
some liability) and are relaxing the requirements.
Notice that those are all system-safety issues stemming from road design.
And none of any of that occurs anywhere in the USA as far as I am aware. A
couple decades ago, I
once walked from a colleague's house in Palo Alto to the California-Street
downtown area, a couple
miles of suburbs. I encountered *no one else* on the sidewalks the entire
journey, until I was in
the downtown area. And the walking was uncomfortable because of the
configuration of the driveway
ramps. Whereas here, people are continually using the sidewalk outside my
house to get to and from
the bus stop and their houses nearly a kilometer up the road. If I come out
just after 6 in the
morning to clear overnight snow, there are often already sets of footprints
from people walking to
the first bus. And I live in a semi-rural village!
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
The System Safety Mailing List
systemsafety at TechFak.Uni-Bielefeld.DE
More information about the systemsafety