Transcript International Study of Highway Development and Management

Introduction and Applications
Transport and Development
Transport sector is vital for economic & social
development
Roads constitute largest component of transport
Roads require a balance of:
Maintenance (or preservation)
Development (or improvement)
Road management requires:
Consistent and rational policy objectives
Sufficient and reliable funding
Effective procedures & management tools
The HDM-4 Model
Analytical decision-making tool, based on
life cycle costs, for:
Engineering and economic assessment of road
construction and maintenance investments
Transport pricing and regulation
Physical and economic relationships derived
from extensive research on:
Road deterioration,
The effects of maintenance activities, and
Road user costs (VOC, VOT, Crash Costs)
Vehicle Emissions & Traffic Noise
HDM-4 Objectives:
Economic basis for selecting investment alternatives
Road standards
Pavement standards
Alignments
HDM-4 Objectives:
StandardMinimize
framework
investigating
roadCosts
investments
Roadfor
Agency
and Road User
Non-motorized
transport facilities
Traffic congestion
Vehicle emissions
Travel times
Transport costs
Road accidents
History of the HDM model
Highway Cost
Model
1971
de Weille
1966
Caribbean Study 1977-82
India Study 1976-82
Brazil Study 1975-84
HDM-III
1987
Kenya Study
1971-75
HDM-II
1981
HDM-4
HDM-VOC
Model 4
2000
1994
ISOHDM
RTIM
(TRRL)
RTIM2
(TRL)
RTIM3
(TRL)
HDM-4 Technology Set
Knowledge
Base
Software
Models
RUE
RDWE
SEE
HDM-4 Series
HDM-4 Concept
Predicts road network performance as a
function of:
Traffic volumes and loading
Road pavement type and strength
Maintenance standards
Environment / Climate
Quantifies benefits to road users from:
Savings in vehicle operating costs (VOC)
Reduced road user travel times
Decrease in number of accidents
Environmental effects
Paved Road Deterioration Model
Moisture,
Temperature
Aging
Traffic,
Loading
Pavement
Materials,
Thickness
Cracking
Raveling
Potholing
Rutting
Roughness
Road User Costs Model
Driver,
Traffic
Flow
Road
Geometry,
Condition
Vehicle
Characteristics
COMPSUMPTION
SPEED
• Fuel & Lubricants
• Tire
• Maintenance Parts & Labor
• Crew Time
• Depreciation & Interest
• Passenger & cargo time
Share of Transport Cost Components
50 veh/day
300 veh/day
Agency Costs
User Costs
5000 veh/day
Optimum Transport Costs
Cost
Total
Optimum
Road Works
Road User
Design Standards
How Credible are HDM-4 Outputs?
Depends on Level of Calibration
(controls bias)
Depends on accuracy and reliability of
input data (asset & fleet characteristics,
conditions, usage)
HDM-4 has proved suitable in a range
of countries
As with any model, need to carefully
check output with good judgement
Approach to Calibration
Input data
Must have a correct interpretation of the
input data requirements
Have a quality of input data appropriate for
the desired reliability of results
Calibration
Adjust model parameters to enhance the
accuracy of its representation of local
conditions
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Bias and Precision
A
Low Bias
High Precision
B
Low Bias
Low Precision
Predicted
Predicted
Data
Data
Observed = Predicted
Observed = Predicted
Observed
C
Observed
High Bias
High Precision
D
Predicted
Observed = Predicted
Predicted
Observed = Predicted
High Bias
Low Precision
Data
Data
Observed
Observed
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Data & Calibration
Need to appreciate importance of data
over calibration
If input data are wrong why worry
about calibration?
Calibration
'The Depth of the Sea and
the Height of the Waves'
Data
Calibration Focus
Road User Effects
Predict the correct magnitude of costs and
relativity of components - data
Predict sensitivity to changing conditions calibration
Pavement Deterioration & Works Effects
Reflect local pavement deterioration rates
and sensitivity to factors
Represent maintenance effects
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Important Considerations
Calibrate over full range of values likely
to be encountered
Have sufficient data to detect the
nature of bias and level of precision
High correlation (r 2) does not always
mean high accuracy: can still have
significant bias
Primary aim: minimize bias
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Calibration: Hierarchy of Effort
Time Required
Experimental
Surveys and
Research
Years
Months
Weeks
Field Surveys
Desk Studies
Limited
Moderate
General Planning
Quick Prioritisation
Preliminary Screening
Project Appraisal
Detailed Feasibility
Coarse Estimates
Reliable Estimates
Significant
Research and
Development
Resources
Required
Calibration Levels
Level 1: Basic Application
Addresses most critical parameters
‘Desk Study’
Level 2: Verification
Measures key parameters
Conducts limited field surveys
Level 3: Adaptation
Major field surveys to requantify
relationships
Long-term monitoring
Sensitivity Classes
Impact
Sensitivity Class Impact Elasticity
High
S-I
> 0.50
Medium
S-II
0.20 – 0.50
Low
S-III
0.05 – 0.20
Negligible
S-IV
< 0.05
Sensitivity Impact
Parameter Important for
2/
3/
Class
Elasticity
Total VOC
S-I
> 0.50 kp - parts model exponent
New Vehicle Price
S-II
S-III
S-IV
Parameter Important for
4/
VOC Savings
kp - parts model exponent
New Vehicle Price
CSPQI - parts model
roughness term
C0SP - parts model constant
term
0.20 - 0.50 Roughness
E0 - speed bias correction
E0 - speed bias correction
ARVMAX - max. rectified
Average Service Life Average velocity
Annual Utilisation
CLPC - labour model exponent
Vehicle Weight
0.05 - 0.20 Aerodynamic Drag Coefficient Beta - speed exponent
Beta - speed exponent
Vehicle Age in km
BW - speed width effect
C0LH - labour model constant
Calibrated Engine Speed
term
CLPC - labour model exponent Labour Cost
C0SP - parts model constant Hourly Utilisation Ratio
term
BW - speed width effects
CSPQI - parts model
Number of tires per Vehicle
roughness term
New tire Cost
Crew/Cargo/Passenger Cost Lubricants Cost
Desired Speed
Crew/Cargo/Passenger Cost
Driving Power
Vehicle Weight
Energy Efficiency Factors
Number of Passengers
Fuel Cost
Hourly Utilisation Ratio
Interest Rate
Projected Frontal Area
<0.05
All Other Variables
All Other Variables
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Sensitivity
Class
Impact
Elasticity
S-I
> 0.50
S-II
0.20 0.50
S-III
0.05 0.20
S-IV
< 0.05
Parameter
Structural Number 2/
Modified Structural Number2/
Traffic Volume
Deflection3/
Roughness
Annual Loading
Age
All cracking area
Wide cracking area
Roughness-environment factor
Cracking initiation factor
Cracking progression factor
Subgrade CBR (with SN)
Surface thickness (with SN)
Heavy axles volume
Potholing area
Rut depth mean
Rut depth standard deviation
Rut depth progression factor
Roughness general factor
Deflection (with SNC)
Subgrade compaction
Rainfall (with Kge)
Ravelling area
Ravelling factor
Outcomes Most Impacted
Pavement
Resurfacing
Economic
Performance
and Surface
Return on
Distress
Maintenance
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Can We Believe HDM-4 Output?
Yes, if sufficiently calibrated
HDM-4 has proved suitable in a range
of countries
As with any model, need to carefully
scrutinize output against judgement
If unexpected predictions occur, check:
Data used
Calibration extent
Check judgment of the expert
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Applications of HDM-4 in
Road Management
Purpose:
To optimise the overall performance of the network over
time in accordance with POLICY OBJECTIVES and within
budgetary constraints
Typical objectives:
Minimise transport costs
Preserve asset value
Provide and maintain accessibility
Provide safe and environmentally friendly transport
Road Management Functions
Planning
Setting standards and policies
Long term estimates of expenditure
Programming
Medium term work programmes
Preparation
Detailed project design and work
packaging
Operations
Implementation of works in field
Role of HDM-4
Management Function
HDM-4 Application
Planning
Strategy Analysis
Programming
Programme Analysis
Preparation
Project Analysis
Standards & Policies
Road pricing
road use costs (to define fuel levies)
congestion charges
weight-distance charges
Vehicle regulations
axle load limits
energy consumption, vehicle emissions & noise
Engineering Standards
sustainable road network size
pavement design and maintenance standards
Technical Standards
What is the optimal traffic threshold for paving?
Net Present Value at 12%
12
10
8
6
4
2
0
-2
-4
-6
100
200
Traffic (ADT)
300
400
Vehicle Policies
9000
Non-vehicle-related
Vehicle-related
Loading-related
8000
7000
6000
5000
4000
3000
2000
1000
Average Daily Traffic (ADT)
10000
6000
3000
1000
0
300
Average Agency Costs ($/km/yr)
How much road damage is caused by trucks?
Strategy Analysis
The analysis of entire road networks
to determine funding needs and/or to predict
future performance under budget constraints
Objectives:
Determine budget allocations for road
maintenance and improvement
Prepare for work programmes
Determine long term network performance
Assess impact on road users
Strategic Analysis Approach
Road Network
G
F
P
Matrix H
M
L
Revenues, Sector budgets
Resource
Constraints
Preservation
Evaluation
Development
Candidates
Optimal Strategy under
Budgetary Constraints
Optimization
Module
Diagnostic of the Network
Roughness in 1998
< 3.5 IRI
28%
> 5.0 IRI
64%
3.5 < IRI <
5.0
8%
Consequences to Society
What are the consequences of budget constraints?
What is the recommended work program?
Society Net Benefits Present Value (Billion Rs)
250
200
150
100
50
0
0
1
2
3
4
5
Periodic Expenditures (Billion Rs/year)
6
Consequences to the Network
Scenario: 6 Billion Rs per year
8.5
80%
7.5
70%
6.5
60%
50%
5.5
40%
4.5
30%
20%
3.5
10%
Year
2004
2003
2002
2001
2000
2.5
1999
0%
Average Roughness (IRI)
90%
1998
Network Condition (%)
100%
Poor
Fair
Good
Avg. IRI
Consequences to the Users
Network Road User Costs (Billion Rs)
250
6 Billion
Rs per
Year
Case
200
150
100
Without
Project
Case
Savings:
152 Billion Rs
50
0
1999
2000
2001
2002
Year
2003
2004
Impact of Budget Levels
Budget
Scenarios
Average Network Roughness (IRI)
(Rs B per year)
9
1.
8
2.
7
6
3.
5
4.
4
6.
3
2
1997
1998
1999
2000
2001
Year
2002
2003
2004
2005
Average Roughness (IRI)
Impact of Budget Allocations
7.0
Feeder
Roads
$30m/yr
6.0
Secondary
Roads
$35m/yr
5.0
Primary
Roads
$20m/yr
4.0
3.0
2003
2004
2005
2006
2007
2008
2009
Programme Analysis
Preparation of single or multi-year
road work and expenditure programmes
under specified budget constraints.
Objective: prioritise candidate road
projects in each year within annual
budget constraint
Annual budgets obtained from strategic
maintenance plan
Work Programme Output
Priority
Rank
1
2
3
4
5
:
1
2
3
:
1
2
3
:
Road
Section
N1-2
N4-7
N2-5
R312-1
R458-3
:
N4-16
R13-23
N521-5
:
N1-6
N7-9
F2140-8
:
Length Province Type of
(km) or District Road Work
20.5
2
Resealing
23.5
7
Overlay 40mm
12.5
5
Reconstruct
30
4
Widen 4 lane
36.2
3
Overlay 60mm
:
:
:
32.1
6
Reconstruct
22.4
4
Overlay 40mm
45.2
2
Widen 4 lane
:
:
:
30.2
4
Resealing
17.8
3
Overlay 60mm
56.1
1
Reconstruct
:
:
:
Scheduled
Year
2000
2003
2000
2003
2000
2003
2000
2003
2000
2003
:
:
2001
2004
2001
2004
2001
2004
:
:
2002
2005
2002
2005
2002
2005
:
:
Cost Cumulative
$m
S$m
5.4
5.4
10.9
16.3
8.6
24.9
31.4
56.3
16.3
72.6
:
22.8
22.8
9.7
32.5
41.3
73.8
:
8.2
8.2
9.2
17.4
34.9
52.3
:
Project Economic Analysis
Project types
New construction, upgrading
Reconstruction, resealing
Widening, lane addition
Non-motorised transport lanes
Economic indicators
Net present value (NPV)
Economic rate of return (ERR)
Benefit cost ratio (BCR), NPV/C
First year rate of return (FYRR)
Economic Decision Criteria
NPV
IRR(3)
NPV/C FYRR
Project economic validity
V.Good
V.Good
V.Good
Poor
Mutually exclusive projects
V.Good
Poor
Good
Poor
Project timing
Fair
Poor
Poor
Good
Project screening (1)
Poor
V.Good
Good
Poor
Under budget constraint (2)
Fair
Poor
V.Good
Poor
Notes:
(1)
Check for robustness to changes in key variables (sensitivity analysis)
(2)
With incremental analysis
(3)
IRR may be indeterminate with NONE or MANY solutions.
Project Level Outputs
Sensitivity analysis results
Scenario analysis
Road condition indicators
Road user cost details
Energy & emissions
HDM-4 Limitations
The model does not:
Perform a network traffic assignment
Internally cost environmental impacts such
as air or noise pollution
Address urban conditions (start/stop)
Evaluate all benefits from very low volume
roads
Software limitations:
Not designed as a road management
database
Conclusions – Why HDM-4?
Transparency of analysis
Economic analysis capable of:
Short, medium & long term analyses
What-if analysis
Internationally accepted analysis
framework
Availability of technical expertise
Local calibration
Web sites:
http://hdm4.piarc.org
http://www.bham.ac.uk/isohdm
http://lpcb.org