1. Introduction and Applications

2. 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
The HDM-4 analytical framework is based on the concept of pavement life cycle analysis. This is applied to predict the following over the life cycle of a road pavement, which is typically 15 to 40 years:
Road deterioration
Road work effects
Road user effects
Socio - Economic and Environmental effects
Once constructed, road pavements deteriorate as a consequence of several factors, most notably:
Traffic loading
Environmental weathering
Effect of inadequate drainage system

3. Life Cycle Analysis Roughness Time / Traffic Loading Road Agency Cost
Rehabilitation
Time / Traffic Loading
Maintenance Standard
Pavement
Performance
Curve
Good
Poor
Road Agency Cost
Rehabilitation
Cost
Time (years)
Cumulative
Maintenance
The figure illustrates the predicted trend in pavement performance represented by the riding quality that is often measured in terms of the international roughness index (IRI). When a maintenance standard is defined, it imposes a limit to the level of deterioration that a pavement is permitted to attain. Consequently, in addition to the capital costs of road construction, the total costs that are incurred by road agencies will include the periodic maintenance, or rehabilitation works applied during the life of a pavement. These in turn depend on the standards of maintenance and improvement specified by HDM-4 users.

4. Rutting Rutting (mm) Pavement Age (Years) Weak Pavement
Strong Pavement
Pavement Age (Years)

5. How long does it take in Bulgaria?
Crack Progression
dACA = annual increase in area cracked
Kcpa = calibration factor
YE4 = traffic loading
SNP = pavement strength
How long does it take in Bulgaria?

6. Crack Progression Calibration

7. Model Calibration

8. Road User Effects Vehicle operating costs Travel time Road accidents
fuel, oil, tyres, parts consumption
vehicle utilisation & depreciation
Travel time
passengers
cargo
Road accidents
Energy consumption
Vehicle emissions & noise
The impacts of the road condition, as well the road design standards, on road users are measured in terms of road user costs, and other social and environmental effects. Road user costs comprise:
Vehicle operation costs (fuel, tyres, oil, spare parts consumption; vehicle depreciation and utilisation, etc.),
Costs of travel time - for both passengers and cargo, and
Costs to the economy of road accidents (that is, loss of life, injury to road users, damage to vehicles and other roadside objects).
The social and environmental effects comprise vehicle emissions, energy consumption, traffic noise and other welfare benefits to the population served by the roads. Although the social and environmental effects of often difficult to quantify in monetary terms, they can be incorporated within the HDM-4 economic analyses if quantified exogenously.
Note that in HDM-4, road user effects can be calculated for both motorised transport (motorcycles, cars, buses, trucks, etc.) and non-motorised transport (bicycles, human powered tricycles, animal pulled carts, etc.).

9. Vehicle Operation Costs
Heavy Truck
Bus
Road User Costs ($/veh-km)
Pickup/utility
Car
The figure illustrates the impact of road condition (represented in terms of the IRI) on the operating costs of different types of vehicles. Road User Costs in HDM-4 are calculated by predicting physical quantities of resource consumption and then multiplying these quantities by the corresponding user specified unit costs. It is necessary to ensure that the vehicle resource quantities predicted are in accordance with the range of values observed in the area of application.
Rickshaw
Good
Road Condition (IRI)
Poor

10. HDM-4 Applications Road sector policy studies
Strategic planning of road network development, improvement & maintenance
Preparation of multi-year road work programs
Economic appraisal of individual road projects
Research studies

11. Strategy Analysis Objectives:
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 2

12. Network Condition Summary
Roughness in 2008
< 3.5 IRI
28%
3.5 < IRI <
> 5.0 IRI
5.0
64% 8%

13. Impact of Budget Levels
Class I Roads
Annual Budget
6.0
$10m
5.0
$15m
Average Roughness (IRI)
4.0
$20m
Target = 3.5 IRI
3.0
2.0
2003
2004
2005
2006
2007
2008
2009

14. Impact of Budget Allocations
Class III
Roads
$30m/yr
Class II
Roads
$35m/yr
Class I
Roads
$20m/yr

15. Program Analysis
Preparation of single or multi-year road work and expenditure programs under specified budget constraints.
Objective: prioritise candidate road projects in each year within annual budget constraint
Annual budgets obtained from strategic maintenance plan

16. Work Program Output
2003
2004
2005

17. Work Program Output (2)

18. Project Economic Analysis
Project types
New construction, upgrading
Reconstruction, resealing
Widening, lane addition
Economic indicators
Net present value (NPV)
Economic rate of return (ERR)
Benefit cost ratio (BCR), NPV/C
First year rate of return (FYRR)

19. Road Management Systems
Data
Collection
Decision
Support
Management
Information
Database
Inventory
Condition
Structures
Traffic
Furniture
Unit Costs
Standards
RDBMS
(RIMS)
Life Cycle
Analysis
(HDM-4)
Standard
& Custom
Reports

20. 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