The Big Impact
Edition 2, June 2014
From the
Director
AS WE head into
the winter months
one might ask why
we are featuring in
the Big Impact,
research that
focuses on cycling;
an often considered
‘good-weather’ modal choice?
Interestingly, across many of our cities we
are beginning to see considerable growth
in cycling across the entire year. The
significance for transport safety is the
associated vulnerability of cyclists given
the current traffic mix in Australian cities.
This issue of the Big Impact features two
studies (one focusing on bicyclists, the
other on motorcyclists) that focus on the
safety in numbers paradigm; a widely
held view in many areas of transport
safety – particularly for vulnerable road
users namely, that the greater the number
of vulnerable road users the safer the
environment. As you will read from our
research, this paradigm is more complex
than previously cited in the research.
As always, I encourage you to view
our recently published papers and
reports; the latter are freely available on
our website. Please contact us if you
wish to discuss any element of our
research.
Professor Mark Stevenson
Director, MUARC
Safety-in-Numbers:
What’s behind the effect?
MUARC research, published in Traffic
Injury Prevention, was recently featured
on the national website, Crikey. The study,
by Mr Jason Thompson, Dr Giovanni
Savino and Professor Mark Stevenson,
looked at the long-held belief that the
more cyclists on the road, the safer
that road is for cyclists. This “safety-innumbers” idea has long been one of the
more popular arguments for boosting the
number of bicycles on our roads and has
weaved its way into many Local and State
Government transport policies.
However, as transport consultant Alan
Davies points out in Crikey, the MUARC
research reveals that (in relation to cyclists)
the safety in numbers effect may not really
be about ‘numbers’ per se. “Rather, what
seems to be the key factor improving
safety is the density/dispersion of cyclists
within a place,” he writes.
In a novel approach to understanding
traffic systems, the researchers created a
simulated, virtual road network containing
thousands of virtual cars. Over time,
an increasing number of cyclists were
introduced to the system. Each vehicle in
u
the system acted on simple ‘give-way’
www.monash.edu/miri/muarc
Safety-in-Numbers: What’s behind the effect? continued
rule in order to try to avoid collisions with
one another. Sometimes, they failed.
According to the researchers, the
safety in numbers effect could easily be
replicated within the simulation, mimicking
the pattern of both route selection and
crash results seen in real world studies.
It could also, however, be just as easily
made to disappear by increasing
the tendency of cyclists to disperse
throughout the road network.
Drawing parallels from herd behaviour
seen in biology, Mr Thompson said that
increasing bicycle density coinciding with
increasing volume may simply reduce
the proportion of surface area per cyclist
exposed to danger from cars. “Fish,
birds, and other flocking species naturally
increase their density in the presence
of threats to reduce risk of predation
by minimising high-risk exposure at the
periphery of groups. The effect is a simple
function of surface area to volume but it
is very effective. We are not saying that
cyclists do this consciously at all, but
increasing cyclist density may have the
same effect”.
The MUARC study suggests that simply
increasing the number of cyclists on the
roads might not improve safety if riders are
dispersed widely across the road network.
Conversely, stable or even decreasing
numbers of cyclists concentrated on high
density routes may make riding safer.
In the Crikey article Mr Davies highlights
the authors’ point that, “It is possible that
cycling ‘activism’ and desire to reclaim
territory from cars in cities where cycling
has experienced a relatively recent cultural
renaissance may inadvertently play a role
in increasing exposure to risk”.
“While there’s no doubt cycling is safer
in places with more cyclists, the reasons
aren’t as straightforward as is commonly
assumed,” he said.
What is the
Safety-in-Numbers
Theory?
THE Safety in Numbers
phenomenon refers to the idea
that the more vehicles there are
on the road the safer the road
becomes for both drivers and
cyclists. In a 2003 study,
Californian engineer, Peter
Jacobsen, first documented the
concept in the journal Injury
Prevention. He found that
doubling the number of cyclists
on the road tends to bring about
a 1/3 drop in the per-cyclist
frequency of a crash with a
motor vehicle. And tripling the
rate of cycling cuts the crash
rate in half.
Coronial Council of Victoria appointment
MUARC Director, Professor Mark Stevenson has been appointed to the Coronial Council of Victoria.
ESTABLISHED under the Coroners
Act 2008 (Vic) to provide advice to the
Attorney-General regarding matters of
importance to the coronial system, the
Council provides advice on:
• the identification of themes, trends
and patterns that may be emerging,
including regional issues
• legislative issues
• proposed law reform activities.
Membership of the council comprises
the State Coroner, the Director of the
Victorian Institute of Forensic Medicine
(VIFM), the Chief Commissioner of
Police and five to seven persons
appointed by the Governor in Council
on the recommendation of the Attorney-
2
www.monash.edu/miri/muarc
General. The Coronial Council of
Victoria is obliged to act in a way that:
• does not impinge on the
independence of coroners’ decisionmaking and investigation of death as
well as the role of the State Coroner
• delivers strategic advice reflecting
the changing physical, social and
political environment to foster a
modern and responsive coronial
system
• promotes and strengthens different
relationships including collaboration
between agencies across the service
system
• focuses on advice to strengthen
services to families and improve the
prevention role of the coroner
• ensures that the views of bereaved
families are reflected in the
development of advice
• complements existing governance
structures in the State coronial
system (for example, the VIFM
Council)
• promotes transparency, accessibility
and accountability regarding the
functions of the Victorian coronial
system.
Professor Pauline Nestor, Senior ViceProvost and Vice-Provost (Research)
at Monash University congratulated
Professor Stevenson on the
appointment which was made on 13
May, 2014.
Study finds the more motorcycles
on the roads the safer for all drivers
Over equivalent distances, the Australian rate of motorcyclist deaths is approximately
30 times the rate for car occupants, with more than 200 motorcyclists killed on
Australian roads annually.
NEW research helps explain the frequency
of motorcycle collisions with cars, finding
drivers are slower to notice motorbikes
when there are fewer motorbikes on the
road.
Dr Vanessa Beanland, formerly from
Monash and now at the Australian National
University’s (ANU) Research School of
Psychology, together with MUARC’s
Professor Mike Lenné and Professor
Geoffrey Underwood, from the University
of Nottingham found motorists would see
and react to motorcycles up to three
seconds faster when more motorbikes
were on the road.
Published in Attention, Perception and
Psychophysics, the researchers revealed
results from a study using a driver
simulator to determine whether an
increased prevalence of motorcyclists in
traffic would improve drivers’ detection of
motorcylcists in traffic.
Forty drivers were involved in the study,
with each participant completing two
drives in the MUARC simulator. Both drives
were on urban roads and the level of traffic
was relatively constant comprising a mix of
motorcycles and vehicles. In the first drive
participants were told to obey normal road
rules and to pay attention to surrounding
traffic, however the prevalence of
motorcycles on road varied significantly. In
the following drive participants essentially
did the same task but also used two
custom-made buttons on the steering
wheel to indicate every time they passed a
bus or a motorcycle. They were also asked
to verbally identify the motorcycle and bus.
This is the first time that a study has
used a simulator to test the safety in
numbers effect. Previously studies
involved the appearance of static images
on a screen.
The study found that the driver was
more likely to notice other road users if
they were more prevalent in traffic.
According to Professor Mike Lenné this
may explain why drivers are less likely to
see motorcycles and take them into
consideration on the road, because they
are generally less common than cars. In
the study – when motorcycles were more
prevalent in the simulator scenario – they
were detected on average 51 metres
away, allowing an extra three seconds for
the driver to respond compared to when
the motorcycles are in low numbers on the
screen.
According to Professor Lenné, the
research has practical implications as it
suggests that many driver errors may
occur because of the driver’s expectations
about the types of vehicles they expect to
encounter on the road.
www.monash.edu/miri/muarc
3
Below is a sample of recent MUARC publications
Thompson J, Savino G, Stevenson
M. Reconsidering the safety in
numbers effect for vulnerable
road users: an application of
agent-based modelling. Traffic
Injury Prevention. 2014 DOI:10.10
80/15389588.2014.914626
Beanland V., Lenne M., Underwood
G, 2014 Safety in numbers: Target
prevalence affects the detection
of vehicles during simulated
driving. Atten Percept Psychophys,
Vol 76: 805-813. DOI: 10.3758/
s13414-013-0603-1
Salmon P., Lenne M., Walker G.,
Stanton N., Filtness A. 2014
Exploring schema-driven
differences in situation awareness
between road users: an onroad study of driver, cyclist and
motorcyclist situation awareness.
Ergonomics. Volume 57 Issue 2,
Pages: 191-209.
Cassell E., Newstead S., 2014. Did
compulsory wear regulations
Further information
Monash University Accident
Research Centre (MUARC)
Building 70, Clayton Campus
Monash University, VIC 3800
Telephone: +61 3 9905 4371
Email: miri-enquiry@monash.edu
4
www.monash.edu/miri/muarc
increase personal flotation device
(PFD) use by boaters in small
power recreational vessels? A
before-after observational study
conducted in Victoria, Australia.
Injury Prevention. Doi:10.1136/
injuryprev-2014-041170
Young K., Salmon P., 2014. Sharing
the responsibility for driver
distraction across road transport
systems: A systems approach to
the management of distracted
driving. Accident Analysis and
Prevention. DOI: 10.1016/j.
aap.2014.03.017
Rizzi M., Strandroth J., Kullgren
A., Tingvall C., Fildes B. 2014.
Effectiveness of Motorcycle
Antilock Braking Systems (ABS)
in Reducing Crashes, the First
Cross-National Study. Traffic Injury
Prevention. DOI:
10.1080/15389588.2014.927575
Tsay A., Savage G., Allen T.,
Proskel U., 2014. Limb position
sense, proprioceptive drift and
muscle thixotropy at the human
elbow joint. 2014. Journal of
Physiology. DOI: 10.1113/
jphysiol.2013.269365
Stevenson M, Johnson M, Oxley J,
Meuleners L, Gabbe B, Rose G.
Safer cycling in the urban road
environment. Injury
Prevention 2014, [10 06
2014]: DOI:10.1136/
injuryprev-2014-0141287
Newnam S, Sheppard DM, Griffin
M, McClure R, Heller G, Sim
M, Stevenson M. Work-related
road traffic injury: a multilevel
systems protocol. Injury
Prevention 2014 doi:10.1136/
injuryprev-2013-041132
Stevenson M, Thompson J. On the
road to prevention: road injury
and health promotion. Health
Promotion Journal of Australia.
2014, 25, 4-7