About the use of D-Sight in the performance evaluation
of road projects for sustainable road safety
Computing and Software for MCDM – MCDM 2011
Renaud Sarrazin
Belgian Road Research Centre, Université Libre de Bruxelles
Yves De Smet
Université Libre de Bruxelles
Quantin Hayez
Decision Sights
21st International Conference on Multiple Criteria Decision Making
Monday 13 June 2011 – Jyväskylä, Finland
Using D-Sight for the evaluation of sustainable road safety
Introduction
«
“Road safety will play an important role in transport policy 2010 – 2020, as
lowering the number of road users' casualties is key to improving the overall
performance of the transport system.”
“In view of achieving the objective of creating a common road safety area, the
Commission proposes to continue with the target of halving the overall number
of road deaths in the European Union by 2020 starting from 2010.”
European Commission, 20/07/2010
Towards a European road safety area: policy orientations on road safety 2011-2020
“Sustainable development is development that meets the needs of the present
without compromising the ability of future generations to meet their own
needs. […] The world must quickly design strategies that will allow nations to
move from their present processes of growth and development onto sustainable
development paths. This will require policy changes in all countries.”
United Nations World Commission on Environment and Development (WCED), 1987
Bruntland rapport – Our Common Future
»
D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
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Using D-Sight for the evaluation of sustainable road safety
Framework of the research

Context
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Framework of the research

Road safety & sustainable development


A posteriori approach (accident statistics)
Economic evaluation only (few or any environmental or social concerns)
→ A priori evaluation (preventive actions)
→ Definition of road safety: elementary triangle of road safety
Accidents in Belgium:
+
From 18% to 28% are related to an
unsafe infrastructure
 More than 55% on rural roads

→ Improve infrastructure-related road safety on rural secondary roads
→ Awareness of sustainable development concerns
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Framework of the research

Design process of an infrastructure
1. Planning
2. Pre-design (draft)
3. Design (detailed)
4. Construction
+
5. Opening &
Exploitation
Objective : evaluating the sustainable road safety performance at
the pre-design stage. Offer to the decision maker a support (i.e.
a decision aid) in the selection of an alternative.
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Research motivations

Multicriteria decision aid problem

Typical MCDA problem:



Alternatives: draft alternatives of a project
Criteria: sustainable road safety performances
Aim: ranking of the alternatives in order to select the best one
» Definition of a set of criteria:



Road infrastructure and road environment performance
Sustainable concerns
Data should be available during the design process
→ Important stage of modelling and creation of data
→ Development of new criteria constitutes a full and complex problem
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Research motivations

Multicriteria decision aid problem
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Methodology – MCDA problem

Definition of a set of criteria

Infrastructure – Road legibility and consistency




To maximise
Driver’s mental representation of the road
Importance of some roadway geometric design elements
Sight distance: distance required to avoid an obstacle on the road or
to stop at an intersection
Fig. 1 - Illustration of the stopping
sight distance when approaching an
intersection (PIARC – MSR, 2003)
→ Control of the adequacy of the operating speed by measuring the
sight distance on the n sections of the road :
C LC 
1
n
n

Min (1;
i 1
d i , op
)
d i , th
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Methodology – MCDA problem

Definition of a set of criteria

Infrastructure – Visibility





To maximise
Roadway elements and equipments which convey visual information
Positive or negative influence
Complex effects (or combination of effects)
Lack of information about this topic
→ Measure of the coefficient of visibility αk of the m roadway elements
and equipments of the road :
CV 
1
m


m
k
k 1
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Methodology – MCDA problem

Definition of a set of criteria

Infrastructure – Safety equipments




To maximise
Prevent run-off accidents or head-on collisions, or reduce them severity
Lack of information about this topic
Temporary scale
→ Measure the influence of safety equipments on the reduction of
accidents severity:
C SE  very bad ; bad ; average ; good ; very good

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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Methodology – MCDA problem

Definition of a set of criteria

Infrastructure – Road surface quality



To maximise
Poor road surface quality + inappropriate speeds = high risk of accidents
Performance indexes about quality parameters


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PIR: transverse evenness
PIS: skid resistance
PID: drainability
PIWC: sensitivity to winter conditions
Fig. 2 – Transverse evenness (BRRC)
Fig. 3 – Sensitivity to winter conditions (BRRC)
Fig. 4 – Drainability (BRRC)
→ Index which measure the global quality of road pavements:
C RS  0 . 45  0 . 7  PI R  0 . 3  PI D   0 . 4  PI F  0 . 15  PI WC
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Methodology – MCDA problem

Definition of a set of criteria

Infrastructure – Protection of Vulnerable Road Users (VRU)



Secondary roads: multimodal nature
High risk of accidents for pedestrians, bicyclists and motorcyclists (VRU)
Development of safety indexes

Bicyclists - Bicycle Safety Index (CBSI):
 Suitable equipments required on straight sections and intersections
 Operating speed of the motorized traffic
 Geometric design parameters
 Volume of traffic
 Roadway equipments
C BSI  0 . 5  C BSI , segment  0 . 5  C BSI , in ters
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Methodology – MCDA problem

Definition of a set of criteria

Infrastructure – Protection of Vulnerable Road Users (VRU)

Pedestrians - Pedestrian Safety Index (CPSI):
 Suitable equipments required on straight sections and crossings

Motorcyclists - Motorcyclist Safety Index (CMSI):
 Slippery surfaces or road markings
 Roadside safety barriers
→ Global safety index to evaluate the level of safety for vulnerable
road users on the road (CVRU):
C VRU  0 . 4  C BSI  0 . 2  C PSI  0 . 4  C MSI
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Methodology – MCDA problem

Definition of a set of criteria

Infrastructure – Work zones
Protection of workers and road users during the reconstruction and
maintenance activities
 Impact on accessibility and costs
 Lack of information about this topic

→ Any criterion has been developed yet
→ Further research

Services – Emergency and Trauma care



To maximise
Evaluation of the quality of the emergency and trauma care services
Complex to define
→ Subjective scale from very bad to very good
→ Further research
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Methodology – MCDA problem

Definition of a set of criteria

Environmental – Greenhouse gases emissions




To minimise
Most frequently used criterion to represent environmental concerns
Construction and maintenance activities
Traffic activities not considered (for the moment)
→ Summing the emissions generated by all the activities of the road:
n
C GHG 

Em GHG , i
i 1

Environmental – Noise pollution




To minimise
Noise generated by the vehicular traffic on the roadway
Very complex (many parameters)
Limitation to the characteristics of the road surface
→ Evaluation of the noise sensitivity of the road surface material
C NP  mat
   noise _ sensitivit y  mat 
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Methodology – MCDA problem

Definition of a set of criteria

Economic – Construction costs and Maintenance costs



To minimise
Evaluation of the economical performance of the road project
Criteria expressed in euros (€)
→ Summing the costs of all the construction or maintenance activities

Social – Mobility and accessibility



To maximise
Accessibility: quantification of the efficiency of a road network
Important to guarantee a good mobility and accessibility of a road
→ Speed Efficiency Coefficient (SEC) which measures the extent of a
road that performs at least as well as the target or threshold speed:
 l v
i
SEC 
i , op
 v i , th 
i
l tot
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Methodology – MCDA problem

Global methodology of the problem
Evaluation and multicriteria
optimisation tool “MULTISED/D-SIGHT”
“MULTISED”
premodelling tool
Parameters of draft
alternatives (inputs)
Data infrastructure (geometry,
design, materials), volume of
traffic, operating speed, safety
equipments, etc.
Evaluation on criteria for each
alternative - Development of
the evaluation table (outputs)
Visibility, legibility and consistency,
protection of VRU, environmental impact,
services, construction and maintenance
costs, etc.
Ranking of the draft alternatives of the
project (PROMETHEE & GAIA) Sensitivity
analysis of the problem
Multicriteria evaluation and selection of
the best draft alternative with respect to
the preferences of the Decision Maker
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Case study

Pilot project : N243a (Walhain, Walloon Brabant, Belgium)


Redevelopment secondary road in a rural area
Main characteristics of the road project:

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

Length: 2.4 km
Number of lanes: 2
Available width: 13.70 m
Intersections: 5
Cycle lane: Yes
Average daily traffic: 3250 vpd
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Case study

Pilot project : N243a
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Type of road surface material
Geometric design parameters
Vertical alignment
Bicyclists equipments
Roadside equipments
Maintenance activities
…
→ 7 draft alternatives
→ Calculation of the evaluation table by using the pre-modelling tool
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Case study

Pilot project : N243a

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Using the D-SIGHT software to assess the quality of these alternatives
Definition of the preferences parameters (column Weights)


On the basis of subjective judgements
Judged not too arbitrary by a road safety expert
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Case study

Pilot project : N243a
Ranking of the 7 draft alternatives (PROMETHEE II net flow scores)
→ Alternatives 3, 4 and 7 seem to be the best according to DM’s preferences

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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Case study
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Pilot project : N243a
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Analysis of the GAIA plane:
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Alternatives and Decision Stick
Some criteria are highly correlated
Two groups of criteria are in opposition: complex problem
DM Brain: complex problem
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Case study
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Case study

Pilot project : N243a


Sensitivity analysis: stability level of the first position
Problem quite robust
X
X
X
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Conclusions and prospects

Conclusions
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Preliminary study
First encouraging results
Many specificities due to the complexity of the road safety theory…
…and the draft design stage of road projects
Innovative concept (preventive approach and recognition of sustainability)
Actual contribution already bring some added value in this application field
Future prospects

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Improvement of the existing set of criteria
Definition of missing criteria
Better understanding of some complex phenomenon about road safety
Recognition of the uncertainty (unpredictable behaviour of road users)
Case study: it will be crucial not to particularize the evaluation
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011
Using D-Sight for the evaluation of sustainable road safety
Thank you for your attention
Questions ?
Renaud Sarrazin
BRRC / CoDE-SMG (ULB)
r.sarrazin@brrc.be
+32/499526143
http://www.brrc.be
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D-Sight and sustainable road safety – MCDM 2011 – 13/06/2011