Learning, Engaging and Acting!
Michael Tziotis, Manager Safe Systems
Targeting Speed Limits –Is there a case for lowering speed limits?
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What do we know about speed and crashes?
Source: Centre for Automotive Research (CASR) SA
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Human tolerance to harmChances of surviving a crash decrease
rapidly above certain impact speed -• car / pedestrian 20 to 30 km/h• car / motorcycle 20 to 30 km/h• car / pole or tree 30 to 40 km/h• car / car (side-impact) 50 km/h• car / car (head-on) 70 km/h
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Travel speed, stopping distance and crash impact speed
Source: VicRoads
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Changes in mean speed and changes in crash risk
-50%
-40%
-30%
-20%
-10%
0%
10%
20%
30%
40%
50%
-10% -8% -6% -4% -2% 0% 2% 4% 6% 8% 10%
% change in speed
% c
han
ge
in c
asu
alti
es
DeathsSerious injuriesOther injuries
Source: Elvik et al. (2004)
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0
5
10
15
20
25
30
35
-15 -10 -5 0 5 10 15 20
Change from the average free speed (km/h)
Rel
ativ
e ri
sk o
f a
casu
alty
cra
sh
60 km/h urban roads
80-110 km/h rural roads
Source: Jurewicz (2009) after Kloeden et al. (2001) and (2002)
Crash risk and speeding
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Evaluation of the 50km/h local street speed limit in NSW – all casualty cashes
0
50
100
150
200
250
Sep-94 Dec-94 Mar-95 Jun-95 Sep-95 Dec-95 Mar-96 Jun-96 Sep-96 Dec-96 Mar-97 Jun-97 Sep-97 Dec-97 Mar-98 Jun-98 Sep-98 Dec-98 Mar-99 Jun-99 Sep-99 Dec-99
Year and month
Nu
mb
er o
f ca
sual
ties
on
50
km/h
str
eets
in T
rial
LG
As,
or
sim
ilar
stre
ets
in t
he
con
tro
l LG
As
Control LGAs
Trial LGAs
Estimated casualties (Control LGAs)
Estimated casualties (Trial LGAs)
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Evaluation of the 50km/h local street speed limit in NSW – actual vs expected
-202.3
-106
-258.7
-300
-250
-200
-150
-100
-50
0
50
Trial LGAs
Dif
fere
nce
in
th
e n
um
ber
of
acci
den
ts
exp
ecte
d c
om
par
ed t
o t
he
actu
al n
um
ber
of
acci
den
ts
UrbanTrial
RuralTrial
Combined Rural and Urban Trial
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Lessons - speed limits LOWERED?
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Lessons - speed limits RAISED?
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NEXT STEP ACTING
Thank You!