Quantified Road Safety Targets: Sustainable Effects

1. Quantified road safety target - Is the effect sustainable? S.C. Wong The University of Hong Kong Tony Sze Delft University of Technology

2. Structure of Presentation • Introduction • Data • Method • Results • Discussions • Conclusions

3. Introduction Road safety strategy framework • FOCUS: Development of objective-related, cost effective, and practical measures that contribute to target achievement

4. Social acceptability Capability Ambition Introduction Achievable and challenging road safety target • 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

5. Short-term effect on average fatality Introduction Previous 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.

6. Long-term effect on trend of fatality Introduction Current perspectives

7. Data Setting road safety target in OECD countries • 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

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

9. y=0 (reference) Data Sample and study period • 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

10. y=0 (reference) Data Sample and study period • 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

11. Data Comparison group

12. Data Comparison group (cont’d)

13. Data Treatment group

14. Scaling factor of annual fatality number at year y, where y = 0 denotes reference year (year preceding a target setting) Method Normalization of fatality data

15. Scaling factor of annual fatality number at year y, where y = 0 denotes reference year (year preceding a target setting) Method Normalization of fatality data

16. Method Qualification test for comparison group 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 )

17. Method Qualification test for comparison group 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,

18. Method Qualification test for comparison group (cont’d)

19. Method Qualification test for comparison group (cont’d)

20. Method Effectiveness evaluation Regression analysis • Regression equation, whereg (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

21. Method Effectiveness evaluation (cont’d)

22. (I) a>0, b>0 (II) a>0, b<0 (III) a<0, b>0 (IV) a<0, b<0 Method Effectiveness evaluation (cont’d) a- absolute change in fatality number b- change in the trend of fatality number

23. Results Effects of quantified road safety target in long term • 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

24. 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

25. 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

26. 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

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