SWOV Workshop, Haarlem, 16 November 2009

Challenge the future

DelftUniversity ofTechnology

Quantified road safety target- Is the effect sustainable?

S.C. Wong The University of Hong KongTony Sze Delft University of Technology

2Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Structure of Presentation

• Introduction• Data• Method• Results• Discussions• Conclusions

3Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

IntroductionRoad safety strategy framework

Policy formulation Policy implementation

VisionObjectiveTargetAction plan

EvaluationQuantitative ModelingInstitutional frameworkFunding

• FOCUS: Development of objective-related, cost effective, and practical measures that contribute to target achievement

4Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

IntroductionAchievable and challenging road safety target

Ambition

Capability

Social acceptability

• When a target is too ambitous, it becomes disappointing with no proven effectiveness, and demotivates

• When a target is too ‘easy’, and can be achieved without a high level of implementation, complacency is induced

• THEREFORE, setting up an appropriate target that strikes a balance among ambition, capability and social acceptability is necessary

5Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

IntroductionPrevious work

• Wong, S.C., Sze, N.N., Yip, H.F. et al. (2006) Association between setting quantified road safety targets and road fatality reduction. Accident Analysis and Prevention 38, 997-1005.

1984 1986 1988 1990 1992 1994 1996 1998 2000

Finland

Netherlands

United Kingdom

Norway

Denmark

Sweden

New Zealand

Spain

Australia

Hungary

Poland

1983 1984 1985 1986 1987 1988 1989 1990

Short-term effect on average fatality

6Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

IntroductionCurrent perspectives

1984 1986 1988 1990 1992 1994 1996 1998 2000

Finland

Netherlands

United Kingdom

Norway

Denmark

Sweden

New Zealand

Spain

Australia

Hungary

Poland1982 1984 1986 1988 1990 1992 1994 1996

Long-term effect on trend of fatality

7Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

DataSetting road safety target in OECD countries

1971 1976 1981 1986 1991 1996 2001 2006

FinlandNetherlands

United KingdomNorway

DenmarkSweden

New ZealandSpain

AustraliaHungary

PolandUnited States

FranceAustriaCanada

Czech RepublicGreeceIreland

ItalyPortugal

SwitzerlandBelgium

GermanyJ apanKorea

Turkey

• 14 OECD countries first set quantified road safety target in 1970s – 1990s

• 7 of which further set a new target before the expiration of 1st target

• 16 OECD countries have no evidence of target setting till year 2001

8Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

DataFatality dataCountry Fatality definition Correction factor

Austria 3 days 1965-1982: +15%1983-1991: +12%

Czech Republic Until 1979: 24 hours Until 1979: +30%

France 1970-1992: 6 days 1970-1992: +9% 1993-2000: +5.7%

Greece Until 1995: 3 days Until 1995: +15%

Hungary Until 1975: 48 hours Until 1975: +20%

Italy 7 days +8%

Japan Until 1992: 24 hours Until 1992: +30%

Korea 3 days +15%

Portugal 24 hours +30%

Spain Until 1993: 24 hours Until 1993: +30%

Switzerland Until 1991: >30 days Until 1991: -3%

Turkey 24 hours +30%

Source of data for current study• International Road Traffic & Accident Database (IRTAD)• World Road Statistics (WRS)

9Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

DataSample and study period

1971 1976 1981 1986 1991 1996 2001 2006

FinlandNetherlands

United KingdomNorway

DenmarkSweden

New ZealandSpain

AustraliaHungary

PolandUnited States

FranceAustriaCanada

Czech RepublicGreeceIreland

ItalyPortugal

SwitzerlandBelgium

GermanyJ apanKorea

Turkey

Sample• 1st target set in OECD countries during the period 1973-1997

Study period for the effect of target setting• y = 1: year of target setting• y = Y: target year

or year preceding setting of new target

y=0 (reference)

10Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

DataSample and study period

1971 1976 1981 1986 1991 1996 2001 2006

FinlandNetherlands

United KingdomNorway

DenmarkSweden

New ZealandSpain

AustraliaHungary

PolandUnited States

FranceAustriaCanada

Czech RepublicGreeceIreland

ItalyPortugal

SwitzerlandBelgium

GermanyJ apanKorea

Turkey

1971 1976 1981 1986 1991 1996 2001 2006

FinlandNetherlands

United KingdomNorway

DenmarkSweden

New ZealandSpain

AustraliaHungary

PolandUnited States

FranceAustriaCanada

Czech RepublicGreeceIreland

ItalyPortugal

SwitzerlandBelgium

GermanyJ apanKorea

Turkey

y=0 (reference)

Sample• 1st target set in OECD countries during the period 1973-1997

Study period for the effect of target setting• y = 1: year of target setting• y = Y: target year

or year preceding setting of new target

11Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

DataComparison group

1971 1976 1981 1986 1991 1996 2001 2006

FinlandNetherlands

United KingdomNorway

DenmarkSweden

New ZealandSpain

AustraliaHungary

PolandUnited States

FranceAustriaCanada

Czech RepublicGreeceIreland

ItalyPortugal

SwitzerlandBelgium

GermanyJ apanKorea

Turkey

12Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

DataComparison group (cont’d)

1971 1976 1981 1986 1991 1996 2001 2006

FinlandNetherlands

United KingdomNorway

DenmarkSweden

New ZealandSpain

AustraliaHungary

PolandUnited States

FranceAustriaCanada

Czech RepublicGreeceIreland

ItalyPortugal

SwitzerlandBelgium

GermanyJ apanKorea

Turkey

13Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

DataTreatment group

1971 1976 1981 1986 1991 1996 2001 2006

FinlandNetherlands

United KingdomNorway

DenmarkSweden

New ZealandSpain

AustraliaHungary

PolandUnited States

FranceAustriaCanada

Czech RepublicGreeceIreland

ItalyPortugal

SwitzerlandBelgium

GermanyJ apanKorea

Turkey

14Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Method

Year 1968 1969 1970 1971 1972 1973 1974 1975 1976

y -4 -3 -2 -1 0 1 2 3 4

Finland 939 1006 1055 1143 1156 1086 865 910 804

United Kingdom 6810 7365 7499 7699 7763 7406 6876 6366 6570

Norway 479 496 560 533 490 511 509 539 471

Denmark 1096 1190 1208 1215 1116 1132 766 827 857

Sweden 1262 1275 1307 1213 1194 1177 1197 1172 1168

Scaling factor of annual fatality number at year y,

where y = 0 denotes reference year (year preceding a target setting)

0

yy

nf n

Normalization of fatality data

15Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Method

Year 1968 1969 1970 1971 1972 1973 1974 1975 1976

y -4 -3 -2 -1 0 1 2 3 4

Finland 0.812 0.870 0.913 0.989 1 0.939 0.748 0.787 0.696

United Kingdom 0.877 0.949 0.966 0.992 1 0.954 0.886 0.820 0.846

Norway 0.978 1.012 1.143 1.088 1 1.043 1.039 1.100 0.961

Denmark 0.982 1.066 1.082 1.089 1 1.014 0.686 0.741 0.768

Sweden 1.057 1.068 1.095 1.016 1 0.986 1.003 0.982 0.978

Normalization of fatality data

Scaling factor of annual fatality number at year y,

where y = 0 denotes reference year (year preceding a target setting)

0

yy

nf n

16Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Regression analysis

• Historical fatality trend in the ‘before’ period

• Trend of log-transformed scaling factor, f and year, y,

where i = t denotes treatment group

i = c (c = 1, 2, 3, … C ) denotes comparison group

α denotes time-series trend of ln (f )

Method

Year 1978 1979 1980 1981 1982 1983 1984 1985

y -7 -6 -5 -4 -3 -2 -1 0

United Kingdom 1.311 1.219 1.143 1.122 1.139 1.045 1.075

Greece 0.981 0.950 0.950 0.880 0.893 0.993 0.986

Italy 1.131 1.181 1.212 1.146 1.094 1.091 1.020

Qualification test for comparison group

ln i if y y

17Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Regression analysis

• Difference in time-series trend between treatment & comparison group

Treatment group

Comparison group

where δ is a dummy variable to signify a comparison group

• Therefore, the regression equation for qualification test,

Method

Year 1978 1979 1980 1981 1982 1983 1984 1985

y -7 -6 -5 -4 -3 -2 -1 0

United Kingdom 1.311 1.219 1.143 1.122 1.139 1.045 1.075

Greece 0.981 0.950 0.950 0.880 0.893 0.993 0.986

Italy 1.131 1.181 1.212 1.146 1.094 1.091 1.020

i t

i t c c c

Qualification test for comparison group

ln , 0i t i i tf y y i t c

18Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Method

Country f ln f y δ-Greece δ-Italy

United Kingdom 1.139 0.130 -1 0 0

United Kingdom 1.045 0.044 -2 0 0

United Kingdom 1.075 0.072 -3 0 0

… … … … … …

Greece 0.893 -0.113 -1 1 0

Greece 0.993 -0.007 -2 1 0

Greece 0.986 -0.014 -3 1 0

… … … … … …

Italy 1.094 0.090 -1 0 1

Italy 1.091 0.087 -2 0 1

Italy 1.020 0.020 -3 0 1

.. … … … … …

Qualification test for comparison group (cont’d)

ln 1, 2,i t i i t Greece Greece Italy Italyf y y y y y y

19Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

MethodQualification test for comparison group (cont’d)

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1974 1976 1978 1980 1982 1984

United Kingdom Greece Italy

Expon. (United Kingdom) Expon. (Greece) Expon. (Italy)

20Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Method

Year 1968 1969 1970 1971 1972 1973 1974 1975 1976

y -4 -3 -2 -1 0 1 2 3 4

Finland 0.812 0.870 0.913 0.989 1 0.939 0.748 0.787 0.696

United Kingdom 0.877 0.949 0.966 0.992 1 0.954 0.886 0.820 0.846

Sweden 1.057 1.068 1.095 1.016 1 0.986 1.003 0.982 0.978

Effectiveness evaluation

Regression analysis

• Regression equation,

where g (y ) = 1 for i = t & y > 0, and g (y ) = 0 if otherwises

h (y ) = a + b y

• Existence of target, g(y )

• Effect of target, h(y )

• a- absolute change in fatality number; b- change in the trend of fatality number

ln i if y y g y h y

21Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Method

Country f ln f y g (y) h (y)

Finland 0.790 -0.236 -9 0 -

Finland 0.834 -0.182 -8 0 -

… … … … … …

Finland 0.989 -0.011 -1 0 -

Finland 1 0 0 0 -

Finland 0.939 -0.062 1 1 a + b

Finland 0.748 -0.290 2 1 a + 2b

… … … … … …

Finland 0.696 -0.363 4 1 a + 4b

Norway 0.757 -0.278 -9 0 -

… … … … … …

Norway 1.043 0.042 1 0 -

Norway 1.039 0.038 2 0 -

… … … … … …

Effectiveness evaluation (cont’d)

ln , 1,..., 2, 1,0,1,2, ,i i i if y y g y h y y a g y b g y y y m m k

22Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

MethodEffectiveness evaluation (cont’d)

ln i if y y g y h y h y a by

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

1978 1980 1982 1984 1986 1988 1990 1992

(I) a>0, b>0

(II) a>0, b<0

(III) a<0, b>0

(IV) a<0, b<0

a- absolute change in fatality numberb- change in the trend of fatality number

23Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Results

• Immediate fatality reduction- consistent to the results of previous study• Desirable changes in the trend of fatality number

• Diminishing the rate of increase• Changing an increase to a decrease• Yielding a greater reduction

Effects of quantified road safety target in long termTreatment country h (y) Comparison group Previous study

Wong & Sze et al. (2006)a b

Finland -0.03 -0.10 11 N/A

United Kingdom 0.10 -0.02* 4 N/A

Norway -0.06 -0.07** 2 -4.7%

Denmark 0.03 -0.03^ 2 -37.7%**

Sweden 0.21** -0.03^ 8 +6.1%

New Zealand -0.04 -0.04^ 4 -8.8%*

Spain -0.31** -0.05* 1 -15.3%**

24Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Discussion

Sustainable goal and target

• Rational, motivating and action guiding goal

• More modest and short-term targets as interim milestones

Comprehensive road safety management framework

• Sub-targets for various road safety indicators

• Periodoic progress review for different road entities and sub-targets

• Robust institutional framework

• Strong political foundation

25Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Discussion (cont’d)

Target setting and fatality reduction

• Intermediate factors between road safety target and fatality reduction

• Factors, circumstances and developments that were anticipated prior

to target setting

26Is the effect of quantified road safety targets sustainable? S.C. Wong and N.N. Sze

Conclusions

Effectiveness of road safety target set in OECD countries (1970s-1990s)

• Regression approach effectiveness evaluation

• Trend of fatality number in a longer time span

• Desirable effect on the trend of fatality number is revealed

Future prospects: a sustainable road safety target

• Ambitiousness of target

• Existence of long-term committment

• Use of sub-targets

• Presence of detailed road safety program

• National income and expenditure on road safety measures

SWOV Workshop, Haarlem, 16 November 2009

Challenge the future

DelftUniversity ofTechnology

Thank you!Quantified road safety target- Is the effect sustainable?S.C. Wong and Tony Sze