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Long-Life Pavement Seminar CEDEX, Madrid, 25 th February 2008

Join the ELLPAG Seminar in Madrid on 25th February 2008 to learn about the economics of long-life pavement. Topics covered include cost-benefit analysis, existing models, and economic aspects of semi-rigid and rigid pavements.

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Long-Life Pavement Seminar CEDEX, Madrid, 25 th February 2008

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  1. Long-Life Pavement Seminar CEDEX, Madrid, 25th February 2008 ELLPAG - Economics of Long-Life Pavement By Nicolas Bueche, EPFL - LAVOC Switzerland

  2. Presentation content • Introduction to economicanalysis • CostBenefitAnalysis (CBA) • Existingmodels for CBA and model choice for long-life pavements • First conclusions on CBA models • Economics of semi-rigid pavements • CostBenefitAnalysis (CBA) methodology • Development of scenarios • Output from the CBA • Conclusions and recommendations • Economics aspects of rigid pavements

  3. Introduction to economicanalysis • Phase 1: Fully-flexible pavements • Consideration of economic aspects through national reports  Method developed to provide a Europe-wide technique for the CBA of LLP, in comparison with determinate life pavements (DLP)

  4. Cost/BenefitAnalysis (CBA) Following aspects must be taken into consideration: • Initial (construction) costs • Loss of capital value – residual value • Maintenance and traffic management costs (agency costs) • Costs due to road user delays at road works • Costs due to accidents • Environmental economical aspects  Some of the costs are relatively easy to determine and calculate but for other types the exercise may be more difficult…

  5. Construction costs • Thickness of LLP couldbelessthan for DLP • Not necessarelyadditionalcosts for LLP (UK) • Someother countries anticipatedhigher construction costs (BE, DK, PL) • More careful construction practices thatmayincrease the unit costs Agencycosts • No structural maintenance • Reduction of maintenance costs not necessarily expected (high quality work needed) • No major difference in traffic management costs expected by UK and Belgium (but operations quicker that may reduce costs)

  6. Loss of capital value • FORMAT project: description of the methodology for the development of a model for evaluating pavement value • helps the assessment of the current value of pavement Accident costs • Somemodelsexist • Verydependent on the traffic and works management • Publishedcostsusuallyavailable and fairlyhigh • NL: €1.3M in 1997 for a fatal accident • UK: currently over €1 for a fatal accident

  7. Costs due to road user delay • Existing models based on comparing traffic flow and residual road capacities. However, these models neglect/underestimate probabilistic aspects of traffic demand (PAV-ECO project, ISOHDM, …) • Statistics usually available in EU countries • NL assessed at €13.5/hour per user Environmentalcosts • Currently no existing global models • Difficult to quantify in monetaryterms • Approach not in use currently but some figures and studiesavailable, especially for noise appreciation and CO2emission (micro-simulation)

  8. Existingmodels for CBA • Enquiryconcerningexisting simple models, thatcouldbeused for CBA on LLP • Following aspects considered: • Assetloss • User costs • Accident costs • Environmentalcosts • Agencycosts

  9. CBA model for LLP EconomicalAssessment • Only UK consideredspecificallyeconomic aspects of LLP: • Pavement maintenance limited to the regular replacement of the surfacing • Underlyinglayersregarded as permanent • Surface treatmentcostssignificantlylessthan structural treatment • Estimatedbenefits for new pavements: • construction benefits: €50M • maintenance costs reduced: €72M • Estimatedcombinedbenefits for new and existing pavements: €350M / 10 years for 10.000 km

  10. Selection of adapted CBA model Review of existing CBA models

  11. Proposed model - PASI • Project AnalysisSystem International • Developed by OECD - long-life surfacing group (2002) • CBA model for long-life pavement economicassetvaluation and whole life costing:  developed for variousenvironments and countries each component (sub-model) is a "simple model" environmental impact not considered simplisticconsideration of someelements

  12. First conclusions on CBA models • Results of the first phase of the project • Different models identified (PASI, FORMAT, ..) • All significant parameters not considered by these models • Development of a specific model for economical assessment of LLP needed • In a first stage, one of the existing model selected, adapted and used for assessing LLP in comparison to traditional alternatives (PASI) • In a second later stage, development is needed of a new model dedicated to LLP that would consider the environmental aspects as well

  13. Full CostBenefitAnalysis

  14. Presentation content • Introduction to economicanalysis • CostBenefitAnalysis (CBA) • Existingmodels for CBA and model choice for long-life pavements • First conclusions on CBA models • Economics of semi-rigid pavements • Cost Benefit Analysis (CBA) methodology • Development of scenarios • Output from the CBA • Conclusions and recommendations • Economics aspects of rigid pavements

  15. Economics of Semi-Rigid (and Flexible) pavements • Phase 2 of the project (under finalisation) • Designs in some European countries • Asphalt layer: functional characteristics and preserve the structural integrity of the structure • Hydraulically bound base layer: primary structural layer Asphalt layer Hydraulically bound base

  16. CBA methodology and assumptions • PASI model used • Main objective: Assess the possible economic savings from the use of LLPs rather than DLPs • Indicative exercise • Maintenance schedules and costs provided from UK's experience • Construction costs not considered explicitly • All maintenance treatments occur exclusively in the bituminous layer

  17. Development of scenarios Parameters defined before any analyses: • Analysis period limited to 50 years in PASI model • Discount rate: rate at which costs and benefits are converted to net present value (NPV) – 3, 5 or 7 % • Parameter variation for the development of scenarios • Identification of key factors which affect the results of the analysis • Sensitivity analysis on these factors  combination of parameter values for the development of scenarios

  18. Development of scenarios

  19. Trafficparameters • Design traffic: 60msa of 80kN standard axles • Annual growth rate: 0%, 1%, 2% • Heavy goods vehicles proportion: 5%, 12%, 20% • Traffic flow (AADT): 50.000, 75.000 and 100.000  Different combinations

  20. Maintenance options • Initial maintenance schedules for LLP1 and DLP1 • LLP: maintenance through regular replacement of the wearing course • DLP initially designed for 20 years life • Further maintenance schedules for determinate life pavements (DLP) to investigate the effect of different maintenance options • LLP2 and LLP3: Effect of maintenance options • LLP4 and LLP5: replace upper layer more frequently than for DLP

  21. Maintenance schedules

  22. Scenarios for the analysis

  23. Output from the CBA Base conditionsDiscount rate: 5% AADT: 75.000 HGVs: 12% Growth Rate: 1% User costs Accident Time delays Vehicle operation

  24. Total costs for the base conditions

  25. Ratio of total cost for DLP1, 2 and 3 to LLP1

  26. Variation in total cost with changes to the AADT

  27. Variation in total costwith discount rate

  28. Conclusions of CBA • Maintenance schedule DLP1 (base case) is: • 2.4 time more expensive than LLP1 • Almost 2.0 times LLP5 • 20 % more than LLP4 • The use of LLPs may generate considerable savings • Degree of saving could be up to 60 % • High potential not compromised by traffic fluctuations • LLP not appropriate in every situation (poor ground,…) • Results and conclusions broadly relevant to both fully flexible and semi-rigid constructions

  29. Limitations of the analytical CBA • Model derived for DLPs and does not take full advantage of LLPs • Residual worth of DLP and LLP not considered • Elaboration of the maintenance scenarios • Frequency of resurfacing (inlay) for LLPs assumed to be similar as for DLPs • CBA conducted with typical UK costs

  30. Recommendations • Disseminate the knowledge of potential benefits of LLPs • Similar studies to be carried out for other European countries with their own costs • Practical experience needs to be developed - for example through full scale trials

  31. Presentation content • Introduction to economicanalysis • CostBenefitAnalysis (CBA) • Existingmodels for CBA and model choice for long-life pavements • First conclusions on CBA models • Economics of semi-rigid pavements • CostBenefitAnalysis (CBA) methodology • Development of scenarios • Output from the CBA • Conclusions and recommendations • Economics aspects of rigid pavements

  32. Economics aspects of rigid pavements • Quality of construction has a big influence in concrete pavements • Similaranalayisprocedure to beused as for semi-rigid pavements • CBA willbelargelybased on the experience in UK and France Poorlyconstructed Wellconstructed

  33. Elaboration of scenarios • Pavement designed for 50 years life duration • Consideration of tworigid pavement types: • Jointedunreinforcedconcrete (URC) • Continuouslyreinforcedconcrete (CRCP) • Trafficparameterswillbesubset of thoseused for semi-rigid pavements • Differentmaintenance options: • Joint treatments • Surface treatments • Structural treatments  Elaboration of maintenance scenarios and PASI simulation yet to becompleted

  34. Thankyou for your attention… nicolas.bueche@epfl.ch

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