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

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e:

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rg.

Photo

gra

pher:

Dan B

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en.

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e:

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edbik

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ages.o

rg.

Photo

gra

pher:

Dan B

urd

en.

Sourc

e:

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w.p

edbik

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ages.o

rg.

Photo

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pher:

Dan B

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en.

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

9

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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kr.

com

.

Photo

gra

pher:

P:B

!rch.

Sourc

e:

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kr.

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:

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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

14

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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rg.

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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:

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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

Olivier.bellefleur@inspq.qc.ca

François Gagnon

514-864-1600, ext. 3627

Francois.gagnon@inspq.qc.ca

Our documents are available in French and English online at:

www.ncchpp.ca.

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