Urban Traffic
Calming
Olivier Bellefleur
François Gagnon
CPHA, Edmonton
June 11th, 2012
Motorized Traffic and Health:
Implementing Interventions to Mitigate Impacts
Outline
Traffic calming: definitions
Political dimensions
The literature review
Health inequalities
-------------------------------------------
Workshop
2
A concept with various uses
3
http://www.ncchpp.ca/175/Publications.ccnpps?id_article=648
1. Calmed new
developments: e.g.
Radburn, N.J.
Source: Wikimedia
Author: Fgrammen
A concept with various uses
4
http://www.ncchpp.ca/175/Publications.ccnpps?id_article=648
“Retrofitting” of existing
street networks through
2. discrete measures
3. systemic measures
Our working definition of traffic calming
5
Interventions on street
networks that involve the
installation of various
measures in order to
reduce speed or volumes
of motorized vehicles
according to one of two
broad approaches:
– Black-spots
– Area-wide
Sourc
e:
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pher:
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en.
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e:
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pher:
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Sourc
e:
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pher:
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Our working definition of traffic calming
6
Interventions on street
networks that involve the
installation of various
measures in order to
reduce speed or volumes
of motorized vehicles
according to one of two
approaches:
Area-wide
Black-spots
Sourc
e:
City
of
Edm
onto
n,
2008,
p.
29.
Sourc
e:
Depart
ment
for
Tra
nsport
, 1999,
p.2
.
Political dimensions
7
Part of strategy to
mitigate impacts
of more car-km
Part of a
strategy to
reduce car-km
Sourc
e:
City
of
Edm
onto
n,
2008,
p.
29.
Sourc
e:
Depart
ment
for
Tra
nsport
, 1999,
p.2
.
http://www.ncchpp.ca/175/publica
tions.ccnpps?id_article=670
Political dimensions
8
Municipal de-normalization of
50km/hr speed limit on residential streets
State codifications of reduced speeds and
new hierarchies of uses of residential streets
Source: Department for Transport, 1999, p.2.
What are the effects of these
two approaches?
Our literature review:
• Methodology
• Logic model
• Results
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http://www.ncchpp.ca/175/Publications.ccnpps?id_article=686
10
Methodology
1. Systematic search of peer-reviewed (n=19) and
grey literature (n=10) for evaluative studies of
urban traffic-calming interventions on four
determinants of health:
Collisions
Sourc
e:
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com
.
Photo
gra
pher:
P:B
!rch.
Sourc
e:
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w.flic
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com
.
Photo
gra
pher:
Info
Cog.
Air quality
Sourc
e:
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w.flic
kr.
com
.
Photo
gra
pher:
beefy
_n1
.
Noise
Sourc
e:
ww
w.flic
kr.
com
.
Photo
gra
pher:
Velo
vote
e.
Active
transportation
Methodology
2. A broader search for
peer-reviewed (n=36) and
grey literature (n=38) to
identify:
• research gaps
• methodological issues
• mechanisms of action
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3. A comparison of
the black-spots and
the area-wide
appoaches
Sourc
e:
Abbott e
t al.,
1995,
p.
9.
E.g., The relationship between speed and
noise
Logic model
12
PRINCIPAL MECHANISMS OF ACTION
EFFECTS ON HEALTH DETERMINANTS
Black-spots approach
TRAFFIC-CALMING POLICY
Reduction of volumes
Reduction of the number and severity of collisions
Reduction of environmental noise
Reduction of speeds Improvement of air quality
Increase in active transportation
Area-wide approach
13
Results: Collisions
• Black-spots and area-wide: substantial reductions in the
number and severity of collisions for all users of the
streets (drivers, cyclists, pedestrians, children, etc.).
Single-lane roundabout:
-77% injury collisions (Retting et al., 2001)
Sourc
e:
ww
w.flic
kr.
com
.
Photo
gra
pher:
WS
DO
T
399 20-mph (32-km/h)
zones in London:
-42% injury collisions
(-49% children) (Grundy et al., 2009)
Sourc
e:
Gru
ndy
et
al.,
2009,
p.
2.
Effectiveness and scale
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Pedestrian black spots* (1999-2003)
Sites where 8 or more pedestrians were injured (37)
*Victim of a road crash that resulted in an
intervention by Urgences-santé
Projection: NAD83, MTM zone 8
Sources: City of Montréal, Urgences-santé
Cartographic prod.: MS Cloutier, 2004
©Direction de santé publique de Montréal
Road network
(Adapted from Morency & Drouin, 2008) (Adapted from Morency & Drouin, 2008)
15
Results: Air quality
• Black-spots and area-wide: increase in
per vehicle emissions (CO2, VOC, CO,
NOX, PM), for most interventions (speed
reduction & speed variations).
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e:
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w.p
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rg.
Photo
gra
pher:
Dan B
urd
en.
An exception:
Replacing stop sings
with a mini-roundabout
• Ambient air quality: little or no effect.
• Area-wide: can reduce overall emissions
(volume reduction).
16
Results: Noise
• Cars: noise reduction, for most interventions (speed
reduction).
Vertical deflections:
• residential streets
• heavy vehicles Source: www.pedbikeimages.org.
Photographer: Dan Burden.
• Heavy vehicles: noise increase, for most interventions
(speed variations and/or vertical deflections).
17
Results: Active transportation
• Perceived road safety: amelioration for pedestrians, parents, and drivers.
A narrowing
adapted for cyclists
Sourc
e:
ww
w.flic
kr.
com
.
Photo
gra
pher:
Gre
g R
ais
man.
• Cyclists: concerned about horizontal deflections and narrowings forcing them closer to moving vehicles.
• Number of active trips: uncertain effects.
• Physical activity: uncertain effects.
Summary
Intervention logic:
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PRINCIPAL MECHANISMS OF ACTION
EFFECTS ON HEALTH DETERMINANTS
Black-spots approach
TRAFFIC-CALMING POLICY
Reduction of volumes
Reduction of the number and severity of collisions
Reduction of environmental noise
Reduction of speeds Improvement of air quality
Increase in active transportation
Area-wide approach
Trucks
Cars
Evidence:
All street users
Total emission, with traffic
volume reductions
Per vehicle emissions
Little or no effect on air
quality
# of active trips and
physical activity
Perceived safety (most
users)
Most promising intervention: •Area wide
•Reduces speeds
•Reduces speed variations
•Reduces traffic volume
•Reduces health inequalities
Transportation and inequalities
Inequalities between who and who?
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• Socio-economic status (SES)
• Income
• Racial traits
• Place of residence
• Mode of transportation
• Age
• Gender
• …
Inequalities of what? • Accessibility
• Collisions, injuries, fatalities
• Air quality
• Noise
• Perceived safety (motorists, cyclists, children, etc.)
• ...
E.g. Collision-related injuries
by Socio-Economic Status group (SES)
20
CIHI, 2008, p.46.
E.g. Noisy or polluted
neighbourhoods by income
21
CIHI, 2011, p.11.
Explanations?
• Traffic volume
• Traffic speed
• Street designs
• Grid pattern
• Etc.
Sourc
e:
NC
CH
PP
.
Photo
gra
pher:
Fra
nçois
Gagnon.
Sourc
e:
NC
CH
PP
.
Photo
gra
pher:
Fra
nçois
Gagnon.
How can traffic calming
reduce inequalities? • Black-spots approach:
– Locations at high risk for collisions are often in low
SES neighbourhoods.
23
Promising strategy to reduce
collision-related injuries
(correlation to inequalities),
but not evaluated
% in
ters
ectio
ns w
ith
art
eri
al
str
ee
ts o
r h
igh
tra
ffic
Ave
rag
e n
um
be
r o
f
inju
rie
s/in
ters
ectio
n
Average income Lowest Highest
Pedestrians
Cyclists
Arterial streets
High traffic
Adapted from Morency, 2009, p.31.
Distribution of collision-related injuries in Montréal
How can traffic calming
reduce inequalities?
24
Collision-related injuries
2 positive evaluations
• Area-wide approach: Giving priority to low SES neighbourhoods:
Promising, but not
evaluated
Pollution (air & noise)
Perceived safety
E.g. 399 20-mph zones
in London, U.K.
25
0
5
10
15
20
25
1 2 3 4 5
Least deprived
Most deprived
% of km of street by deprivation quintile covered by
20-mph zones in 2006
Source of data:
Grundy et al., 2008, p.39.
0
100
200
300
400
500
600
700
1 2 3 4 5
Least deprived
Most deprived
Pre
vente
d inju
ries
Prevented injuries in 2006
Adjacent streets
In 20-mph zones
Source of data:
Grundy et al., 2008, p.40.
26
E.g. Two similar cities, U.K.
Most affluent
Most deprived 0
2
4
6
8
10
1992-1994 1995-1997
1998-2000
Child
pedestr
ian in
jury
rate
(4
-16 y
ear
old
s;
0/0
0)
City A (U.K.)
Source of data:
Jones et al., 2005
Most affluent
Most deprived 0
2
4
6
8
10
1992-1994 1995-1997
1998-2000
Child
pedestr
ian n
jury
rate
(4
-16 y
ear
old
s;
0/0
0)
City B (U.K.)
Source of data:
Jones et al., 2005
0
1
2
3
4
5
6
Most affluent
Next affluent
Next deprived
Most deprived
Density
(n.b
. tr
aff
ic c
alm
ing
mesure
s/s
treet km
)
City A
City B
Source of data:
Jones et al., 2005
Distribution of traffic-calming measures by SES zones
Unintended effects on
inequalities?
People of low SES tend
to be overrepresented
near major roads
+
Burdens from
transportation are
already high
27
Intervention logic:
PRINCIPAL MECHANISMS OF ACTION
EFFECTS ON HEALTH DETERMINANTS
Black-spots approach
TRAFFIC-CALMING POLICY
Reduction of volumes
Reduction of the number and severity of collisions
Reduction of environmental noise
Reduction of speeds Improvement of air quality
Increase in active transportation
Area-wide approach
Modal transfer (to cycling, …)
Traffic diversion (from one
local street to another or from
local streets to major roads)
A simple framework…
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…near the intervention? …where some of the
motorized traffic might be
diverted?
What are the anticipated effects
of an intervention on the main
determinants of health...
Positive effects:
Negative effects:
Traffic diversion: Yes/No?
Positive effects:
Negative effects:
Who lives, works, studies, etc.,...
Who benefits?
Who bears the burden?
Traffic diversion: Yes/No?
Who benefits?
Who bears the burden?
Who travels by what mode (car,
cycling, walking, etc.)...
Who benefits?
Who bears the burden?
Traffic diversion: Yes/No?
Who benefits?
Who bears the burden?
…with a temporal dimension
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…near the
intervention?
…where some of the
motorized traffic might
be diverted?
What are the anticipated
effects of an
intervention on the main
determinants of health...
Positive effects:
Negative effects:
Traffic diversion:
Yes/No?
Positive effects:
Negative effects:
Who lives, works,
studies, etc.,...
Who benefits?
Who bears the burden?
Traffic diversion:
Yes/No?
Who benefits?
Who bears the burden?
Who travels by what
mode (car, cycling,
walking, etc.)...
Who benefits?
Who bears the burden?
Traffic diversion:
Yes/No?
Who benefits?
Who bears the burden?
Short term
Medium term
Long term
Effects over time?
Traffic patterns over time?
Mode split over time?
Movement of vulnerable
populations over time?
References
• Abbott, P., Tyler, J., & Layfield, R. (1995). Traffic calming: vehicle noise emissions alongside speed control cushions and road humps (Report No.
TRL 180). Crowthorne, Berkshire: Transport Research Laboratory.
• Bellefleur, O. & Gagnon, F. (2011). Urban Traffic Calming and Health: A Literature Review. Montréal: National Collaborating Centre for Healthy Public
Policy. Retrieved from: http://www.ncchpp.ca/docs/ReviewLiteratureTrafficCalming_En.pdf
• Canadian Institute for Health Information. (2008). Reducing Gaps in Health: A Focus on Socio-Economic Status in Urban Canada. Ottawa: CIHI.
Retrieved from: http://secure.cihi.ca/cihiweb/products/Reducing_Gaps_in_Health_Report_EN_081009.pdf
• Canadian Institute for Health Information. (2011). Urban Physical Environments and Health Inequalities. Ottawa: CIHI. Retrieved from:
http://secure.cihi.ca/cihiweb/products/cphi_urban_physical_environments_en.pdf
• Department for Transport. (1999). Leigh Park Area Safety Scheme, Havant, Hampshire (Report No. Traffic Advisory Leaflet 2/99). London: TSO.
Retrieved from: http://www.ukroads.org/webfiles/TAL%202-99%20Leigh%20Park%20Area%20Safety%20Scheme%20-%20Havant%20-
%20Hampshire.pdf
• Edmonton, the City of. (2008). Motor Vehicle Collisions 2007. Edmonton. Retrieved from:
http://www.edmonton.ca/transportation/RoadsTraffic/2007_Annual_Collision_Report_FINAL.pdf
• Gagnon, F. & Bellefleur, O. (2011a). Traffic Calming: An Equivocal Concept. Montréal: National Collaborating Centre for Healthy Public Policy. Retrieved
from: http://www.ncchpp.ca/docs/ConceptTrafficCalming_EN.pdf
• Gagnon, F. & Bellefleur, O. (2011b). Traffic Calming: Political Dimensions. Montréal: National Collaborating Centre for Healthy Public Policy. Retrieved
from: http://www.ncchpp.ca/docs/PolDimensions_TrafficCalming_En.pdf
• Grundy, C., Steinbach, R., Edwards, P., Green, J., Armstrong, B., & Wilkinson, P. (2009). Effect of 20 mph traffic speed zones on road injuries in
London, 1986-2006: controlled interrupted time series analysis. BMJ, 339, b4469. doi: 10.1136/bmj.b4469
• Grundy, C., Steinbach, R., Edwards, P., Wilkinson, P., & Green, J. (2008). The Effect of 20 mph zones on Inequalities in Road Casualties in London: A
report to the London Road Safety Unit. London: London School of Hygiene and Tropical Medicine. Retrieved from:
http://www.tfl.gov.uk/assets/downloads/the-effect-of-20-mph_-zones-on-inequalities_in-road-casualties-in-london.pdf
• Jones, S. J., Lyons, R. A., John, A., & Palmer, S. R. (2005). Traffic calming policy can reduce inequalities in child pedestrian injuries: database study.
Injury Prevention, 11, 152-156. doi: 10.1136/ip.2004.007252
• Morency, P. (2009). Blessés de la route, des inégalités qui s’expliquent. Développement social, 10(2), 31.
• Morency, P. & Drouin, L. (2008). Traffic Calming. Evidence for Action. Presentation at the workshop Evidence and policy making at Journées annuelles
de santé publique. Retrieved from: http://www.ncchpp.ca/docs/PMorency_LDrouin_TAaisement_EN.pdf
• Retting, R. A., Bhagwant, P. N., Garder, P. E., & Lord, D. (2001). Crash and Injury Reduction Following Installation of Roundabouts in the United States.
American Journal of Public Health, 91(4), 628-631.
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Thanks!
Olivier Bellefleur
514-864-1600, ext. 3635
François Gagnon
514-864-1600, ext. 3627
Our documents are available in French and English online at:
www.ncchpp.ca.
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