Difficulties in Implementing the Road Safety Impact Assessment process

1. International Road Federation
Road Safety Impact Assessment
{ Quantification Challenges for Worldwide
Application
Basil Psarianos, Professor
National Technical University of Athens,
Greece
Providing Infrastructure that improves Road Safety
Bucharest, May 10-11, 2011

2. Directive 2008/96/EC on Road Infrastructure Safety Management
ONLY for the Trans-European Road Network
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3. Road
Road Safety
Road Safety Road Safety Network
Impact
Audits Inspections Safety
Assessment
Management
PROACTIVE
Road Safety Impact Assessment: A Proactive
Design Decision Process for Road Safety
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4.  Strategic Level of Decision Making for Road Design
and Planning
 New Roads and Substantial Modifications of
existing Roads
 Safety Implications of Design and Planning
Alternatives
 Safe Route Planning
 All Road Projects
 Prerequisite for Approval of any Road Project
 Safety Considerations associated with Alternative
selected
 Cost-beneficial Component of Alternative
AIM of RIA for New & Old Roads
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5.  Elements of a road safety impact assessment:
(a) problem definition;
(b) current situation and ‘do nothing’ scenario;
(c) road safety objectives;
(d) analysis of impacts on road safety of the proposed alternatives;
(e) comparison of the alternatives, including cost-benefit analysis;
(f) presentation of the range of possible solutions.
 Elements to be taken into account:
(a) fatalities and accidents, reduction targets against ‘do nothing’ scenario;
(b) route choice and traffic patterns;
(c) possible effects on the existing networks (e.g. exits, intersections, level
crossings);
(d) road users, including vulnerable users (e.g. pedestrians, cyclists,
motorcyclists);
(e) traffic (e.g. traffic volume, traffic categorization by type);
(f) seasonal and climatic conditions;
(g) presence of a sufficient number of safe parking areas;
(h) seismic activity.
RIA Content
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6.  Denmark
 Germany
 Finland
 Lithuania
 Netherlands
 Portugal
 Slovakia
RIA: An Old Story (more or less)
for some Members States
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7.  One Dimensional (Major Roadwork, Road Facility,
Reconstruction)
 Engineering Judgment
 Literature Review
 Local Network Impact
 C-B Analysis
 Two Dimensional (Areal Level)
 Baseline Situation (year 0)
 Future Situation w/o Measures (Autonomous
Development)
 Road Safety Alternatives
 C-B Analysis
 Optimization of Alternatives for best C-B ratio
Two Types of RIA
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8. The Achilles Heel:
Quantification
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9. Road Safety?
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10. There is actually NO Safety!
Instead there is RISK
RISK (R) is a combination of Crash
Severity (SH) and its Probability (p):
 R=SH*p or
R   p(SH)  d(SH)
Safety Impact Assessment
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11. Different Sections and Characters (after H. Heinz)
A:Local Entrance Street
B:Local Entrance Street D:Central Square F:Local Entrance Street
C:Shopping Street E:Shopping Street G:Local Entrance Street
VII SEMINARIO
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12. Can Someone define EXACTLY for each Section the
appropriate:
 Design Speed?
 Cross-Section?
 Curvature?
 Intersection Form and Type?
 Equipment?
 Traffic Characteristics?
 ETC?
Safety Impact Assessment
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13. Evidence-Based Road Safety:
The conscientious
and judicious use of
{ current best evidence
in providing
road safety for
individuals,
facilities, and
transportation
systems.
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14. RISK LOSS
Number _ of _ Crashes Number _ of _ Victims
Roadsafetyimpact  Exposure  
Exposure Number _ of _ Crashes
Safety Impact Assessment
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15. • E(λ)=Expected Number of Accidents
• Q=Traffic Volume for Major & Minor
Road
• β=Elasticity
• γi=Coefficients
• xi=Risk Factors
•
Usual Prediction Model
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16. Example: Motorways
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17. Accident Modification Factors (AMF)
Accident Modification Factor is a constant
or equation that represents the change in
safety following a change in the design or
operation of a facility.
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18. Crash Reduction Factor: CRF
Crash Reduction Factor is a
constant that represents the portion
of crashes reduced as a result of a
safety improvement (e.g., add a left-
turn bay)Reduction location or
Crash at a specific Factor:
along a specific road segment.
CRF
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19. CRF:
Nw
CRF  1
Nw / o
CRF = crash reduction factor associated with a specific improvement;
Nw = expected number of crashes with the improvement, crashes/yr;
and
Nw/o = expected number of crashes without the improvement,
crashes/yr.
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20. Providing Infrastructure that improves Road Safety
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21. Volumes change on Network: RIA
on Network
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22. Volumes???
Motorway Attiki Odos
Motorway Korinthos-Patra
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23. Experience on Traffic Forecasts
Source: Halkias, B., Tyrogianni; H.:
PPP Projects inInfrastructure that improves Road Safety Tollway, Route-Roads No. 342, 2008
Providing
Greece: The Case of Attika
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24. % Errors in Traffic Forecasts (Flybjerg et al., 2006)
underestimation overestimation
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25. •Accident Data
•Network Data
•Road Characteristics
•User Behavior
Input •Etc
•Technical
•Juridical
Intervention •Etc
Scenarios
•Total Costs of Measures
•Crash Modifications
•Presentation of Alternative Measures (scenarios) for comparison
Output
GIS-Support Tool
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26. SEROES Expert System
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27. Safety Impact Assessment:
Example
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28. Safety Impact Assessment:
Example continued
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29. Safety Impact Assessment:
Cost?
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30. By EZRA HAUER
Cost-Benefit Analysis
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31. By Ezra Hauer,
TRB 2011
Cost-Benefit Analysis
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32. By Ezra Hauer,
TRB 2011
Cost-Benefit Analysis
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33. By Ezra Hauer,
TRB 2011
Cost-Benefit Analysis
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34. Public Consensus: For Example Access
Management
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35. Typical Example: people assess property
rights higher than road safety
Public consensus, ie is prohibition of property
access possible?
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36. Road Safety Impact
Assessment
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37. QUANTIFICATION
PROBLEMS
 Knowledge Gap
 Data Sets
 Modelling
 Calibration Factors
 Statistical Evidence
 Traffic Forecasting
 CBA Weaknesses
RIA: Conclusions
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38. Setup a Plan and Action
Program at International
/ EU and National / Local
Level to address the
quantification problems
of Road Safety Impact
Assessment and get the
public consensus for it!
RIA: Conclusions
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Bucharest, May 10-11, 2011 38

39. RIA: Conclusions
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40. Engineer’s Role in Informal
RIA Application
 SAFETY: NOMINAL vs SUBSTANTIVE SAFETY i.e.
 Guidelines vs Performance, or
 Rhetoric vs Reality
 FLEXIBILITY to make Professional Design Choices
AND Assuming Responsibility for them
 PRACTICAL DESIGN
RIA: Conclusions
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41. International Road Federation
Basil Psarianos,
Nat’l Tech. Univ. Athens, Greece
bpsarian@mail.ntua.gr
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