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Introduction and Applications

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:

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Introduction and Applications

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  1. Introduction and Applications

  2. 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

  3. 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 derivedfrom extensive research on: • Road deterioration, • The effects of maintenance activities, and • Road user costs (VOC, VOT, Crash Costs) • Vehicle Emissions & Traffic Noise

  4. HDM-4 Objectives: Road standards Pavement standards Alignments Economic basis for selecting investment alternatives

  5. HDM-4 Objectives: Non-motorized transport facilities Traffic congestion Vehicle emissions Travel times Transport costs Road accidents Standard framework for investigating road investments Minimize Road Agency and Road User Costs

  6. History of the HDM model RTIM (TRRL) RTIM2 (TRL) RTIM3 (TRL) HDM-4 2000 ISOHDM

  7. HDM-4 Technology Set Knowledge Base Software Models RUE SEE RDWE

  8. HDM-4 Series

  9. 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

  10. Paved Road Deterioration Model Moisture,TemperatureAging Traffic,Loading PavementMaterials,Thickness Cracking Raveling Potholing Rutting Roughness

  11. Road User Costs Model Driver,TrafficFlow RoadGeometry,Condition VehicleCharacteristics SPEED • Fuel & Lubricants • Tire • Maintenance Parts & Labor • Crew Time • Depreciation & Interest • Passenger & cargo time COMPSUMPTION

  12. Share of Transport Cost Components 50 veh/day 300 veh/day 5000 veh/day Agency Costs User Costs

  13. Optimum Transport Costs Cost Total Optimum Road Works Road User Design Standards

  14. 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

  15. 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 3

  16. Bias and Precision 13

  17. Data & Calibration • Need to appreciate importance of data over calibration • If input data are wrong why worry about calibration?

  18. 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 5

  19. 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 15

  20. Calibration: Hierarchy of Effort

  21. 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

  22. Sensitivity Classes

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  25. 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 23

  26. 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

  27. 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

  28. Role of HDM-4

  29. 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

  30. Technical Standards What is the optimal traffic threshold for paving? 200 300 400

  31. Vehicle Policies How much road damage is caused by trucks?

  32. Strategy Analysis • Objectives: • Determine budget allocations for road maintenance and improvement • Prepare for work programmes • Determine long term network performance • Assess impact on road users The analysis of entire road networks to determine funding needs and/or to predict future performance under budget constraints

  33. Strategic Analysis Approach Road Network G F P H Matrix M L PreservationEvaluation Resource Constraints Revenues, Sector budgets Development Candidates Optimal Strategy underBudgetary Constraints OptimizationModule

  34. Diagnostic of the Network

  35. Consequences to Society What are the consequences of budget constraints? What is the recommended work program?

  36. Consequences to the Network

  37. Consequences to the Users

  38. Impact of Budget Levels

  39. Impact of Budget Allocations Feeder Roads $30m/yr Secondary Roads $35m/yr Primary Roads $20m/yr

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

  41. Work Programme Output 2003 2003 2003 2003 2003 2004 2004 2004 2005 2005 2005

  42. 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) Project Economic Analysis

  43. 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.

  44. Project Level Outputs • Sensitivity analysis results • Scenario analysis • Road condition indicators • Road user cost details • Energy & emissions

  45. 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

  46. 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

  47. Web sites: http://hdm4.piarc.org http://www.bham.ac.uk/isohdm http://lpcb.org

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