Life Cycle Cost Analysis Procedures Manual November, 2007
LIFE- CYCLE COST ANALYSIS
PROCEDURES MANUAL
Note to the User
To use this manual, the reader must have the life- cycle cost analysis software program RealCost, Version 2.2 California Edition. The program can be downloaded from:
http:// www. dot. ca. gov/ hq/ esc/ Translab/ OPD/ DivisionofDesign- LCCA. htm
November 2007
State of California
Department of Transportation
Pavement Standards Team & Division of Design
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Life Cycle Cost Analysis Procedures Manual November, 2007
DISCLAIMER
This manual is intended for the use of Caltrans and non- Caltrans personnel on projects on the State Highway System regardless of funding source. Engineers and agencies developing projects off the State Highway System may use this manual at their own discretion. Caltrans is not responsible for any work outside of Caltrans performed by non- Caltrans personnel using this manual.
ACKNOWLEDGMENT
The information contained in this manual is a result of efforts of many individuals in the Department of Transportation, Pavement Standards Team, Division of Design, and the University of California, Partnered Pavement Research Center. Questions regarding this manual should be directed to Mario Velado at ( 916) 227- 5843 or Mario_ Velado@ dot. ca. gov.
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Life Cycle Cost Analysis Procedures Manual November, 2007
TABLE OF CONTENTS
CHAPTER 1 - INTRODUCTION.................................................................................................. 8
1.1 Purpose of This Manual........................................................................................................ 8
1.2 Background..................................................................................................................... ..... 8
1.3 Caltrans’ Policy..................................................................................................................... 9
CHAPTER 2 - LCCA................................................................................................................... 11
2.1 Design alternatives............................................................................................................. 12
4.1.1 Provisions for Selecting Design Alternatives........................................................... 12
4.1.2 Selecting Design Alternatives................................................................................... 15
2.2 Analysis Period................................................................................................................... 17
2.3 Discount Rate...................................................................................................................... 19
2.4 Maintenance and Rehabilitation Sequences....................................................................... 20
2.5 Estimating Costs................................................................................................................. 24
2.5.1 Initial Costs................................................................................................................... 25
2.5.2 Maintenance Costs........................................................................................................ 26
2.5.3 Rehabilitation Costs...................................................................................................... 27
2.5.4 User Costs..................................................................................................................... 34
2.5.5 Remaining Service Life Value...................................................................................... 35
2.6 Calculating Life- Cycle Costs.............................................................................................. 35
CHAPTER 3 - Using RealCost..................................................................................................... 37
3.1 Methodology.................................................................................................................... .. 37
3.2 Installing & Starting RealCost........................................................................................... 39
3.3 Project Inputs...................................................................................................................... 41
3.3.1 Project Details............................................................................................................... 41
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Life Cycle Cost Analysis Procedures Manual November, 2007
3.3.2 Analysis Options........................................................................................................... 43
3.3.3 Traffic Data................................................................................................................... 45
3.3.4 Value of User Time...................................................................................................... 51
3.3.6 Added Time and Vehicle Stopping Costs..................................................................... 54
3.3.7 Save Project- Level Inputs............................................................................................. 56
3.3.8 Alternative- Level Inputs.............................................................................................. 56
3.5 Input Warnings and Errors.................................................................................................. 69
3.6 Simulation and Outputs...................................................................................................... 70
3.7 Administrative Functions.................................................................................................... 73
CHAPTER 4 – Analyzing LCCA Results.................................................................................... 74
4.1 Status of the LCCA Procedures Manual....................................................................... 75
4.2 RealCost....................................................................................................................... 75
4.2.1 Project Conditions and RealCost.............................................................................. 76
4.3 Agency and User Costs................................................................................................. 77
4.3.1 Limitations of LCCA Results................................................................................... 78
4.3.2 Comparing Agency & User Costs............................................................................. 79
4.3.3 Choosing an Alternative........................................................................................... 80
4.4 Projects with Different Pavement Design Lives........................................................... 80
REFERENCES..................................................................................................................... ....... 81
APPENDIX 1: glossary and list of acronyms............................................................................... 82
APPENDIX 2: List of RealCost Limitations and Bugs............................................................... 88
APPENDIX 3: Productivity estimates of typical m& r strategies................................................. 89
APPENDIX 4: Typical Pavement M& R Schedules for California.............................................. 90
APPENDIX 5: TRAFFIC INPUTS ESTIMATION................................................................... 126
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Life Cycle Cost Analysis Procedures Manual November, 2007
APPENDIX 6: ALTERNATE PROCEDURE FOR CALCULATING CONSTRUCTION YEAR AADT........................................................................................................................... ............. 132
APPENDIX 7: Weekend traffic hourly distribution.................................................................. 134
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Life Cycle Cost Analysis Procedures Manual November, 2007
LIST OF FIGURES
FIGURE 2- 1: PAVEMENT CONDITION VS. YEARS............................................................................ 19
FIGURE 2- 2: PAVEMENT M& R SCHEDULE DETERMINATION FLOW CHART................................... 21
FIGURE 2- 3: EXAMPLE OF PAVEMENT M& R SCHEDULE............................................................... 23
FIGURE 3- 1: REALCOST SWITCHBOARD.......................................................................................... 40
FIGURE 3- 2: PROJECT DETAILS PANEL.......................................................................................... 42
FIGURE 3- 3: ANALYSIS OPTIONS PANEL........................................................................................ 42
FIGURE 3- 4: DESIGN DESIGNATION............................................................................................... 43
FIGURE 3- 5: TRAFFIC DATA PANEL............................................................................................... 45
FIGURE 3- 6: TRAFFIC INFORMATION............................................................................................. 46
FIGURE 3- 7: VALUE OF USER TIME PANEL.................................................................................... 52
FIGURE 3- 8: TRAFFIC HOURLY DISTRIBUTION PANEL WITH CALIFORNIA WEEKDAY DEFAULT VALUES......................................................................................................................... ....... 53
FIGURE 3- 9: ADDED TIME AND VEHICLE STOPPING COSTS PANEL................................................ 54
FIGURE 3- 10: TYPICAL ALTERNATIVE PANEL ( ALTERNATIVE 1 SHOWN).................................... 57
FIGURE 3- 11: INPUT WARNINGS.................................................................................................... 70
FIGURE 3- 12: DETERMINISTIC RESULTS PANEL............................................................................. 71
FIGURE 3- 13: REALCOST REPORT................................................................................................... 72
FIGURE A4- 1. MAP OF CALTRANS CLIMATE REGIONS................................................................... 91
FIGURE A5- 1. TRAFFIC DEMAND- CAPACITY MODEL.................................................................. 129
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LIST OF TABLES
TABLE 2. LCCA ANALYSIS PERIODS............................................................................................. 18
TABLE 3. AGENCY PROJECT SUPPORT COST MULTIPLIERS............................................................ 26
TABLE 4. ESTIMATED CONSTRUCTION COSTS OF TYPICAL M& R STRATEGIES FOR FLEXIBLE PAVEMENTS...................................................................................................................... .... 28
TABLE 5A. ESTIMATED CONSTRUCTION COSTS OF TYPICAL M& R STRATEGIESFOR RIGID & COMPOSITE PAVEMENTS........................................................................................................ 29
TABLE 5B. ESTIMATED CONSTRUCTION COSTS OF TYPICAL M& R STRATEGIES FOR RIGID & COMPOSITE PAVEMENTS........................................................................................................ 30
TABLE 6. TRAFFIC INPUT VALUES................................................................................................. 50
3.3.5 TRAFFIC HOURLY DISTRIBUTION.......................................................................................... 52
TABLE 7. TRANSPORTATION COMPONENT CONSUMER PRICE INDEXES......................................... 55
TABLE 8. PRODUCTIVITY ESTIMATES OF TYPICAL FUTURE REHABILITATION STRATEGIES FOR FLEXIBLE PAVEMENTS........................................................................................................... 63
TABLE 9. PRODUCTIVITY ESTIMATES OF TYPICAL FUTURE REHABILITATION FOR RIGID AND COMPOSITE PAVEMENTS........................................................................................................ 63
TABLE 9. PRODUCTIVITY ESTIMATES OF TYPICAL FUTURE REHABILITATION FOR RIGID AND COMPOSITE PAVEMENTS........................................................................................................ 64
TABLE 14. CALTRANS CLIMATE REGION CLASSIFICATION............................................................ 90
TABLE 15. PASSENGER CAR EQUIVALENT FACTORS.................................................................... 126
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Life Cycle Cost Analysis Procedures Manual November, 2007
CHAPTER 1 - INTRODUCTION
1.1 Purpose of This Manual
This manual describes Life- Cycle Cost Analysis ( LCCA) procedures to be used on pavement projects on the State Highway System, regardless of funding source. The manual provides step- by- step instructions for using RealCost, a macro inside EXCEL, developed by the Federal Highway Administration ( FHWA). RealCost was chosen by Caltrans as the official software for evaluating the cost effectiveness of alternative pavement designs for new roadways or for existing roadways requiring CApital Preventive Maintenance ( CAPM), rehabilitation, or reconstruction. RealCost and the manual can be accessed from the Caltrans Website at http:// www. dot. ca. gov/ hq/ esc/ Translab/ OPD/ DivisionofDesign- LCCA. htm. This manual provides the guidelines required to perform an LCCA and will help to assure that project alternatives are analyzed objectively and consistently statewide, regardless of who designs, builds, or funds the project.
1.2 Background
LCCA is an analytical technique that uses economic principles in order to evaluate long- term alternative investment options. The analysis enables total cost comparison of competing design alternatives with equivalent benefits. LCCA accounts for relevant costs to the sponsoring agency, owner, operator of the facility, and the roadway user that will occur throughout the life of an alternative. Relevant costs include initial construction ( including project support), future maintenance and rehabilitation, and user costs ( time and vehicle costs). The LCCA analytical process helps to identify the lowest cost alternative that accomplishes the project objectives by providing critical information for the overall decision- making process. However, some instances the lowest cost option may not ultimately be selected after such considerations as available budget, risk, political, and environmental concerns are taken into account. 8
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1.3 Caltrans’ Policy
FHWA encourages the use of LCCA for the evaluation of all major investment decisions in order to increase the effectiveness of those decisions. It is Caltrans’ policy that the cost impacts of a project’s life- cycle are fully taken into account when making project- level decisions for pavements1.
Life- cycle cost analysis must be performed, using the procedures and data in this manual. LCCA must be performed for all projects that include pavement work on the State Highway System except:
•
Major maintenance ( HM- 1)
•
Minor A and Minor B
•
Permit Engineering Evaluation Reports ( PEER)
•
Maintenance pullouts
•
Landscape paving
For the exempted projects, the project manager and the project development team will determine on a case- by- case basis if a life- cycle cost analysis should be done and how it should be documented for each project development phase.
When the alternative with the lowest life- cycle cost is not selected, the reasons must be documented. Procedures for how to document life- cycle costs in project documents can be found in Appendix O- O of the Project Development Procedures Manual ( PDPM).
1 See Memorandum “ Use of Life Cycle Cost Analysis for Pavements” by Richard Land, Chief Engineer dated March 7, 2007.
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Pavement work consists of all the work associated with constructing a pavement structure, including subgrade, subbase, base, surfacing, and pavement drainage. It can consist of constructing, widening, rehabilitating, or overlaying lanes, shoulders, gore areas, intersections, parking lots, or other similar activities.
This manual is intended to provide the procedures required to implement the LCCA policies. The manual will be updated with new data and information periodically or as required. Additional information can be found in Chapter 8 of the PDPM and in Topics 612 and 619 of the Highway Design Manual ( HDM). Where conflicts in information or requirements exist or are perceived to exist, the information in this manual shall supersede the information in the PDPM and HDM.
Highway Design Manual Topics 612 and 619 identify situations where a LCCA must be performed to assist in determining the most appropriate alternative for a project by comparing the life- cycle costs of different:
1)
Pavement types ( flexible, rigid, or composite);
2)
Rehabilitation strategies;
3)
Pavement design lives ( e. g., 5 vs. 10 years, 10 vs. 20 years, 20 vs. 40 years, etc.); and
4)
Implementation strategies ( combining widening and rehabilitation projects vs. building them separately).
If a change in pavement design alters the pavement design life or other performance objectives during the design of the project, the LCCA must be updated.
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Life Cycle Cost Analysis Procedures Manual November, 2007
CHAPTER 2 - LCCA
Once the decision has been made to undertake a project, a life- cycle cost analysis ( LCCA) should be completed as early as possible in the project development process. Caltrans practice is to perform a LCCA when scoping a project ( Project Initiation Document phase) and again during the Project Approval & Environmental Document phase ( PA& ED). There are two different approaches in life- cycle cost computation: deterministic and probabilistic. The deterministic approach is the traditional methodology in which the user assigns each LCCA input variable a fixed, discrete value usually based on historical data and user judgment. The probabilistic approach is a relatively new methodology that accounts for the uncertainty and variation associated with input values. The probabilistic approach allows for simultaneous computation of different assumptions for many variables by defining uncertain input variables with probability distributions of possible values. Probability distribution functions for individual LCCA input variables are still under development by Caltrans and are not yet available for use. Therefore, Caltrans only uses the deterministic approach at this time.
The elements required to perform a LCCA are:
1)
Design alternatives;
2)
Analysis period;
3)
Discount rate;
4)
Maintenance and rehabilitation sequences;
5)
Costs;
6)
RealCost software
The LCCA procedures described herein were derived from the FHWA’s RealCost User Manual ( 2004) and LCCA Technical Bulletin ( 1998), “ Life- Cycle Cost Analysis in Pavement Design,”
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and the Life- Cycle Cost Analysis Primer ( 2002). The additional tables, figures, and other resources included in this manual are specifically developed for Caltrans projects to guide the data inputs needed for running RealCost.
2.1 Design alternatives
A LCCA begins with the selection of alternative pavement designs that will accomplish same performance objectives for a project. For example, comparisons can be made between flexible vs. rigid pavements; rubberized asphalt concrete ( RAC) vs. conventional hot mixed asphalt ( HMA) pavements; HMA mill- and- overlay vs. HMA overlay; and 20- year vs. 40- year pavement design lives. Each competing alternative, if properly designed, must be a viable pavement structure that is both constructible and cost effective for that type and life of pavement.
4.1.1
Provisions for Selecting Design Alternatives
When selecting design alternatives for the LCCA, the following provisions must be met:
1)
Compare pavement alternatives with different design lives, At least two of the competing alternatives must have the same type of surface material. [ i. e. Flexible: HMA, RAC, Rigid: Jointed Plain Concrete Pavement ( JPCP), etc]. When comparing a flexible and a rigid pavement alternative, but with different pavement design lives, another flexible alternative matching the design life of the rigid alternative must be analyzed. Exceptions to this provision include situations where no standard design with an alternate design life exists for the pavement surface in question. [ Examples: no standard flexible pavement design for a Traffic Index ( TI) > 15; no continuously reinforced concrete pavement ( CRCP) designs for High Mountain or High Desert climate regions].
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2)
Rubberized Asphalt Concrete ( RAC) must be one of the competing alternatives when flexible pavement is being considered unless RAC is not viable for the project. If RAC is not a viable alternative, justification must be included in the Project Initiation Document ( PID) or the Project Report ( PR). For further information on when and how to use RAC, see HDM Index 631.3 and the Asphalt Rubber Usage Guide.
3)
During the PID phase, LCCA must at least determine which alternate pavement design life is the most cost effective. HDM Topic 612 provides the minimum requirements used to determine the pavement design lives for each type of project. Caltrans currently investigates the following alternate pavement design lives:
•
10- year
•
20- year
•
40- year
•
CAPM projects: no specific design life, 5- year anticipated service life
•
Widening projects: match remaining service life of adjacent roadway
Note:
Remaining service life ( RSL) is determined by the District Maintenance or Materials Engineer by estimating, in 5- year increments, how much life ( before a CAPM project will be needed) remains in the existing pavement adjoining the widening project. Per HDM Index 612.3, the pavement design life of the widening cannot be less than the design period ( HDM 103.2) of the project. For example, if the existing pavement on a widening project has an estimated RSL of 15 years and the design period for the widening project is 20 years, then the pavement design life for the widening project is 20 years.
4)
Determine the type of pavement surface ( flexible, rigid, or composite; HMA vs. RAC, JPCP vs. CRCP) during the PID phase for rehabilitation and CAPM projects. For new construction 13
Life Cycle Cost Analysis Procedures Manual November, 2007
or widening projects, determination of the pavement surface type can be deferred until the PA& ED phase ( if desired by the district) because information is often limited during the PID phase. Preliminary decisions made during the PID phase regarding pavement type must be verified during the PA& ED phase.
If the type of pavement surface cannot be determined during the PID phase and the construction budget will be programmed using the PID document, determine the pavement costs as follows:
a)
For widening:
•
Select the same pavement type as the existing ( flexible, rigid, or composite), except when the TI > 15 use composite pavement in lieu of flexible pavement. ( Caltrans currently does not have a flexible pavement design for TI > 15)
•
If flexible is the expected alternative, assume the surface type is RAC
b)
For new construction:
•
TI < 10: assume flexible pavement
•
10 < TI < 15: assume rigid or flexible pavement. Historically, Caltrans has used rigid pavement on freeways and expressways, and flexible pavement on conventional highways. If there is uncertainty which alternative is best for the project situation, the alternative with the higher initial cost should be selected
•
15 < TI < 17: assume rigid or composite pavement
•
TI > 17: assume CRCP as the preferred rigid pavement alternative
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5)
For new construction projects with a 20- year TI > 10, a LCCA analysis comparing rigid or composite and flexible pavement alternatives must be done at the PA& ED phase, even if an analysis was previously completed during the PID phase.
6)
The alternatives being evaluated must provide equivalent improvements or benefits. For example, comparison of 20- year and 40- year rehabilitation alternatives or comparison of new construction of flexible or rigid pavement alternatives is valid because the alternatives offer equivalent improvements. Comparison of lane replacement versus overlay is also equivalent. Conversely, comparing pavement rehabilitation to new construction, overlay to widening, or rehabilitations at different project locations do not result in equivalent benefits. Projects that provide different benefits should be analyzed using a Benefit- Cost Analysis ( BCA), which considers the overall benefits ( safety, environmental, social, etc.) of an alternative as well as the costs. For further information on BCA, refer to the Life- Cycle/ Benefit- Cost Model ( Cal- B/ C) user manuals and technical supplements, which are available from the Division of Transportation Planning website at http:// www. dot. ca. gov/ hq/ tpp/ tools. html.
4.1.2
Selecting Design Alternatives
Table 1 provides some alternatives that will meet the above requirements. To use the table, determine the following information:
1)
The pavement project type. Pavement project types are divided into 4 categories: new construction/ reconstruction, widening, CAPM, and roadway rehabilitation. The HDM Topic 603 provides definitions for each of the projects.
2)
The document associated with the design phase of the project, such as the Project Initiation Document ( PID), the Project Report ( PR), or the Project Scope and Summary Report ( PSSR). Draft project reports are considered to be the same as project reports.
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3)
The condition of the project. Conditions are based on the 20- year TI ( new construction), existing pavement surface ( for widening rehabilitation, CAPM) and the pavement type and design life selected in the PID, for project reports.
After obtaining the information identified above, identify the row in the table that best represents the project. The table provides three preferred alternatives ( Alternatives 1, 2, and 3) for each condition and some additional alternatives that may be added to ( or in some cases substituted for) the three preferred alternatives. Select the alternatives that best suit the project conditions while still meeting the provisions specified in Section 2.1.1. Please note that Table 1 is not a complete list of all possible alternatives for a particular project.
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Pvmt Project TypeDocumentConditionsAlt 1Alt 2Alt 3PID20- yr Traffic Index ( TI20) TI20 > 1520- yr Rigid ( JPCP) 40- yr Rigid ( JPCP) 40- yr Rigid ( CRCP) 20- yr Flex( 1) 20- yr Composite( 2) 40- yr Composite( 2) 12< TI20 < 15 20- yr Flex( 3) 40- yr Rigid ( JPCP) 40- yr Flex( 3) 40- yr Rigid ( CRCP) 20- yr Composite( 2) 40- yr Composite( 2) TI20 < 1220- yr Flex( 3) 40- yr Rigid ( JPCP) 40- yr Flex( 3) 20- yr Composite( 2) 40- yr Composite( 2) PR ( PA& ED) PID Preferred Pvmt Type & Design LifeFlexible ( 20- yr design) Flex ( HMA) Flex ( RAC) Rigid ( JPCP) Flex ( HMA w/ OGFC) Flex ( RAC- G w/ RAC- O) Flex ( HMA w/ RAC) Flexible ( 40- yr design) Flex ( HMA w/ OGFC) Flex ( RAC- G w/ RAC- O) Rigid ( JPCP) Flex ( HMA w/ RAC) Rigid ( CRCP) Rigid ( 20- yr design) Rigid ( JPCP) Flex ( RAC) Flex ( HMA) Rigid ( 40- yr design) Rigid ( JPCP) Rigid ( CRCP)( 4) Flex ( RAC w/ RAC- O) Composite( 2) Flex ( HMA w/ RAC) Composite ( 20- yr design) Composite ( HMA) Composite ( RAC) Flex ( HMA) Flex ( RAC) Rigid ( JPCP) Flex ( HMA w/ RAC) Composite ( 40- yr design) Composite ( HMA) Composite ( RAC) Rigid ( JPCP) Rigid ( CRCP) Flex ( RAC- G w/ RAC- O) Flex ( HMA w/ RAC) PIDExist Road Pvmt SurfaceFlexible RSL Flex20- yr Flex40- yr Flex40- yr Composite( 2) 20- yr Composite( 2) RigidRSL RigidRSL Flex40- yr Rigid Composite( 5) RSL Composite20- yr Flex40- yr Composite20- yr CompositeRSL FlexPR ( PA& ED) PID Preferred Pvmt Type & Design LifeFlexible (< 20- yr design) HMAHMA w/ RACRACHMA w/ OGFCRAC- G w/ RAC- OFlexible (> 20- yr design) HMA w/ RACRAC- G w/ RAC- OHMA w/ OGFCRigid (< 20- yr design) RigidFlex ( RAC) Flex ( HMA) Rigid (> 20- yr design) RigidFlex ( RAC- G w/ RAC- O) Flex ( HMA w/ OGFC) Composite( 5) (< 20- yr design) Composite ( HMA) Composite ( RAC) Flex ( RAC) Flex ( HMA) RigidComposite( 5) (> 20- yr design) Composite ( RAC) Flex ( RAC- G w/ RAC- O) Flex ( HMA w/ OGFC) Composite ( HMA) PRExist Road Pvmt SurfaceFlexibleHMARAC HMA w/ RACHMA w/ OGFCRAC- G w/ RAC- ORigid (< 5% slab replacement) Grinding ( Rigid Strategy) Thin RAC Overlay Rigid (> 5% slab replacement) Grind & Slab ReplacementsLane Replacement ( Rehab Strategy) Composite( 6) PSSRExist Road Pvmt SurfaceFlexibleHMARACHMA w/ OGFCRAC- G w/ RAC- OFlexible w/ OGFC or RAC- OHMA w/ OGFCRAC- G w/ RAC- ORigid 10- yr Crack, Seat & Flex Overlay20- yr Crack, Seat & Flex Overlay40- yr Lane Replacement20- yr Lane Replacement40- yr Crack, Seat & Flex Overlay( 1) Composite( 5) 10- yr Overlay20- yr Overlay40- yr Lane Replacement20- yr Lane ReplacementRoadway RehabilitationUse Flexible CAPM AlternativesCAPM Table 1Typical Alternatives for Various Types of Projects with PavementOther Alternatives that could be consideredNewWideningNotes: can opt to analyze HMA vs RAC in addition to rigid pavement alternatives. ( 4) Consider only for TI20 > 12. ( 5) Includes previously built crack, seat, and Flexible overlay projects* Refer to Appendix 1, " Glossary and List of Acronyms" for definitions of terms used in the table. ( 2) Composite Pvmt may be thin Flex (< 0.25') over JPCP or CRCP. Choose the same rigid pvmt type that is being analyzed for one of the other alternatives. Assume RAC for flexible surface unless it is desired to analyze both RAC and HMA alternatives or RAC is not viable ( see HDM 631.3) ( 3) Assume RAC unless there are specific reasons RAC cannot be used. Document these reasons in Project Initiation Documents. If sufficient information is available, ( 1) Highway Design Manual ( HDM) currently does not provide a methodology for this design. Consult the Office of Pavement Design for special design options.
2.2 Analysis Period
The analysis period is the period of time during which the initial and any future costs for the project alternatives will be evaluated. Table 2 provides the common analysis periods to be used Life Cycle Cost Analysis Procedures Manual November, 2007
when comparing alternatives of a given design life or lives. For example, a minimum analysis period of 35 years should be used if 10- year and 20- year design life alternatives are compared, or if two different design alternatives with the same 20- year design life are compared. Alternative Design LifeCAPM10- Yr15 or 20- Yr25 to 40- YrCAPM20 years20 years20 years10- Yr20 years20 years35 years55 years15 or 20- Yr20 years35 years35 years55 years25 to 40- Yr55 years55 years55 years
Table 2. LCCA Analysis Periods
LCCA assumes that the pavement will be properly maintained and rehabilitated to carry the projected traffic over the specified analysis period. As the pavement ages, its condition will gradually deteriorate to a point where some type of maintenance or rehabilitation treatment is warranted. Thus, after the initial construction, reasonable maintenance and rehabilitation ( M& R) strategies must be established for the analysis period. Figure 2- 1 shows the typical relationship between pavement condition and pavement life when appropriate maintenance and rehabilitation strategies are applied in a timely manner.
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Note: see Appendix 1, “ Glossary and List of Acronyms,” for definitions of terms used in the figure.
Figure 2- 1: Pavement Condition vs. Years
Additional information about M& R strategies for various types of pavements can be found in Section 2.4, “ Maintenance and Rehabilitation Sequences.”
2.3 Discount Rate
Discount rate is the interest rate by which future costs ( in dollars) will be converted to present value. In other words, it is the percentage by which the cost of future benefits will be reduced to present value ( as if the future benefit takes place in the present day). Real discount rates ( as opposed to nominal discount rates) reflect only the true time value of money without including the general rate of inflation. Real discount rates typically range from 3% to 5% and represent the prevailing interest of U. S. Government 10- year Treasury Notes. Caltrans currently uses a discount rate of 4% in the LCCA of pavement structures. 19
Life Cycle Cost Analysis Procedures Manual November, 2007
2.4 Maintenance and Rehabilitation Sequences
After viable project alternatives are identified and the project information is gathered, a pavement M& R schedule for each alternative must be determined. Pavement M& R schedules identify the sequence and timing of future activities that are required to maintain and rehabilitate the pavement over the analysis period. Pavement M& R schedules found in Appendix 4 of this manual must be used in the LCCA for pavement projects on the State Highway System. To determine the applicable pavement M& R schedule for a project alternative in Appendix 4, the following information is needed:
1)
Existing/ New Pavement Type. The types are: flexible, rigid, and composite.
2)
Pavement Climate Region. This is obtained from the map in Figure A4- 1, which is also available on the Pavement Engineering website.
3)
Final Pavement Surface Type or Project type for existing Regid Pavements. The final pavement surface type is the alternative being investigated for LCCA. Options include HMA, HMA with Open Graded Frictional Course ( OGFC), RAC Gap Graded ( RAC- G), or RAC Gap Graded with RAC Open Graded ( RAC- G w/ RAC- O), JPCP, and CRCP.
4)
Pavement Design Life. See the HDM Topic 612 for guidance.
5)
Maintenance Service Level ( MSL). MSL is the state highway classification used by the Division of Maintenance for maintenance program purposes. Refer to Appendix 1, “ Glossary and List of Acronyms,” for further definition of MSL.
Once all the above information is known, refer to Figure 2- 2 to select the appropriate pavement M& R schedule in Appendix 4. Note that table type ( F or R), climate region and final pavement type are shown at the top of each M& R schedule ( see Figure 2- 3). After selecting the appropriate M& R schedule, select the final project type, pavement design life, and Maintenance Service Level ( MLS) for the project alternative being considered. Finally, select the alternative that closely matches the project alternative being considered and follow the rehabilitation sequence.
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Figure 2- 2: Pavement M& R Schedule Determination Flow Chart
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22
Figure 2- 3 shows an example of the Pavement M& R Schedules found in Appendix 4 for RAC pavements in the State’s “ coastal” climate region. The M& R schedule tables have been derived from the “ Pavement M& R Decision Trees” prepared by each Caltrans district and experience with pavement performance in California ( Note: these schedules assume there will be no early failures). As shown in the Figure 2- 3, the M& R schedules include the initial alternative as well as the future CAPM, rehabilitation, or reconstruction activities and their estimated service lives ( see “ Activity Service Life ( years)” box in Figure 2- 3. Interim maintenance treatments such as Major Maintenance ( HM- 1) projects and work by maintenance field crews performed between each scheduled activity have been converted into an annualized maintenance cost in dollars per lane mile ($/ lane- mile). Life Cycle Cost Analysis Procedures Manual November, 2007
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Figure 2- 3: Example of Pavement M& R Schedule
Life Cycle Cost Analysis Procedures Manual November, 2007
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EAMPLE 2.1
Suppose that one of the alternatives being considered for flexible pavement is a “ CAPM HMA w/ RAC” located in the coastal climate region with a maintenance service level of 2. To determine the appropriate pavement M& R schedule, go to the “ F” tables since the existing pavement is a flexible pavement. Since the project is in the coastal region, select the M& R schedules with the heading “ All Coastal Regions”. Next, find among the selected schedules the one that addresses the final pavement type for the alternative being considered, for this example “ Hot Mix Asphalt W/ RAC”. Thus, the appropriate schedule will have the heading “ Table F- 1, All Coastal Climate Regions, Hot Mix Asphalt w/ RAC Pavement Maintenance and Rehabilitation Schedule”. Finally, knowing that the project type is a CAPM and the MSL is 2, we can find the appropriate row and sequence. In this example the sequence is the sixth from the top. From this schedule it can be determined that the HMA w/ RAC CAPM alternative is expected to last 10 years and the annualized cost for maintenance ( HM- 1) is estimated at $ 3,500 per lane- mile. The M& R schedule also calls for a “ 10- year Rehab HMA w/ RAC” at year 10 after the implementation of the CAPM alternative. This rehab is expected to last up to 10 years with an annualized maintenance cost of $ 2,200 per lane- mile.
2.5 Estimating Costs
Life- cycle costs include two types of cost: agency costs and user costs. Agency costs include initial, maintenance, rehabilitation ( including CAPM), support, and remaining service life value costs. User costs include the additional travel time and related vehicle operating costs incurred by the traveling public due to potential congestion associated with planned construction throughout the analysis period. Life Cycle Cost Analysis Procedures Manual November, 2007
2.5.1 Initial Costs
Initial costs must include estimated construction costs as well as project support costs ( for design, environment, construction administration and inspection, project management, etc.) to be borne by an agency for implementing a project alternative.
2.5.1.1 Construction Costs
For each alternative, the initial construction costs ( first activity in the M& R sequence) should be determined from the engineer’s estimate. Costs for mainline and shoulder pavement, base and subbase, drainage, joint seals, earthwork, traffic control, time- related overhead, mobilization, supplemental work, and contingencies should be included. Construction costs that will not change between alternatives — such as bridges, traffic signage, and striping — may be excluded if those costs can be separated from the rest of the estimate. See the PDPM for information and work sheets for estimating costs in the PID and the PR.
2.5.1.2 Project Support Costs
Costs for project support should be estimated based on the costs identified in the proposed work plan for a project alternative. When work plan data is not yet available, use the project support cost multipliers shown in Table 3 with the initial construction costs to estimate project support costs for a project alternative.
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Table 3. Agency Project Support Cost Multipliers Multiplier w/ Multiplier w/ oRight- of- WayRight- of- WaySmall750,000 - 5,000,0000.470.39Medium5,000,001 - 20,000,0000.310.29Large20,000,001 - 35,000,0000.250.23Very Large 35,000,001 - Up0.240.20Small750,000 - 2,500,0000.560.52Medium2,500,001 - 5,000,0000.390.35Large5,000,001 - 15,000,0000.280.26Very Large15,000,001 - Up0.250.24Small750,000 - 2,000,0000.190.19Medium2,000,001 - 5,000,0000.180.15Large5,000,001 - Up0.160.13Small750,000 - 2,000,0000.350.31Medium2,000,001 - 5,000,0000.280.26Large 5,000,001 - Up0.200.19* Refer to Appendix 1, " Glossary and List of Acronyms" for definitions of terms used in table. CAPM Roadway RehabilitationType of ProjectRange of Project ($) New Construction/ ReconstructionWidening
Example 2.2:
Consider a future HMA overlay CAPM project with a construction cost estimate of $ 4.0 million. The corresponding project support cost multipliers in Table 3 for this CAPM alternative are 0.18 with right- of- way and 0.15 without right- of- way, respectively. Accordingly, the estimated initial cost for this alternative is $ 4.72 million ($ 4.0 million X 1.18 = $ 4.2 million. $ 4.0 million for construction and $ 0.72 million for project supports) with right- of- way acquisition and $ 4.6 million ($ 4.0 million X 1.15 = $ 4.6 million. $ 4.0 for construction and $ 0.6 million for project supports) if the project does not require right- of- way.
2
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schedules in Appendix 4. These annualized costs are based on the “ Pavement M& R Decision Trees” prepared by each Caltrans district and historical cost data collected by the Division of Maintenance.
2
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Table 4. Estimated Construction Costs of Typical M& R Strategies for Flexible Pavements CAPM Overlay99,000Mill & Overlay 118,000Overlay146,000Mill & Overlay 165,000Overlay161,000Mill & Overlay 180,000Overlay100,000Mill & Overlay 119,0005+ Overlay147,0005+ Mill & Overlay 162,000Rehabilitation299,00020332,00010 318,000 20351,000346,000379,00010365,000398,00010361,00020394,00010380,00020413,00010327,00020363,00010346,00020379,00010389,00020422,0 010408,00020441,000Lane ReplaceNotes: * Refer to Appendix 1, " Glossary and List of Acronyms" for definitions of terms used in the table. ** Lane- mile construction costs excluding project support costsRAC w/ RAC- OSee Table 5b for options101020205+ 5+ 5+ 5+ 5+ 5+ Mill & OverlayHMA w/ RACRACHMA w/ OGFCHMA w/ RACOverlayMill & OverlayOverlayOverlayHMAMill & OverlayMill & OverlayHMARACRAC w/ RAC- OHMA w/ OGFCPvmt. Design Life ( years) 5+ 5+ Mill & Overlay OverlayOverlayFuture M& R Activity Description$/ Lane- MileFinal Surface Type Life Cycle Cost Analysis Procedures Manual November, 2007
Table 5a. Estimated Construction Costs of Typical M& R Strategiesfor Rigid & Composite Pavements 81,00084,00091,000Conc. Pvmt Rehab A( 1) ( with RSC of 12- Hour Curing Time) 123,000Conc. Pvmt Rehab A( 1) ( with RSC of 4- Hour Curing Time) 148,000Conc. Pvmt Rehab B( 2) ( with RSC of 12- Hour Curing Time) 88,000Conc. Pvmt Rehab B( 2) ( with RSC of 4- Hour Curing Time) 106,00082,000Conc. Pvmt Rehab C( 3) ( with RSC of 4- Hour Curing Time) 89,000Punchout Repairs A( 6) ( with RSC of 12- Hour Curing Time) 163,000Punchout Repairs A( 6) ( with RSC of 4- Hour Curing Time) 175,000Punchout Repairs B( 7) ( with RSC of 12- Hour Curing Time) 136,000Punchout Repairs B( 7) ( with RSC of 4- Hour Curing Time) 147,00020,000Punchout Repairs C( 8) ( with RSC of 4- Hour Curing Time) 25,000Punchout Repairs C( 8) ( with RSC of 12- Hour Curing Time) Rigid - Continuously Reinforced Concrete Pavement ( CRCP) 5+ 5+ 5 +/- Pvmt. Design Life ( years) 5+ 5+ 5 +/- 5+ $/ Lane- Mile( 4) Final Pavement TypeFlexible / CompositeRigid - Jointed Plain Concrete Pavement ( JPCP) CAPMConc. Pvmt Rehab C( 3) ( with RSC of 12- Hour Curing Time) Flexible Overlay w/ JPCP Slab Replacements( FO + JPCP SR, RSC 4- Hour Curing Time) Flexible Overlay + JPCP Slab Replacements( FO + JPCP SR, RSC 12- Hour Curing Time) Future M& R Activity DescriptionFlexible Overlay* Refer to Appendix 1, " Glossary and List of Acronyms" for definitions of terms used in the table. Notes: ( 1) Conc Pvmt Rehab A involves pavement grinding, significant slab replacement, spall repair, & joint seal repair. It is for projects with a total number of slabs in the lane that exhibit third state Rigid Cracking or were previously replaced is greater than or equal to 5% and less than or equal to 7%. For greater than 7%, the project should be scoped and analyzed as a roadway rehabilitation project. ( 2) Conc Pvmt Rehab B involves pavement grinding, moderate slab replacement, spall repair, & joint seal repair. It is for projects with a total number of slabs in the lane that exhibit third state Rigid Cracking or were previously replaced is between 2 and 5%. ( 3) Conc Pvmt Rehab C involves pavement grinding, minor slab replacement, spall repair, & joint seal repair. It is for projects with a total number of slabs in the lane that exhibit third state Rigid Cracking or were previously replaced is between 2% or less. For greater than 7%, the project should be scoped and analyzed as a roadway rehabilitation project. ( 4) Lane- mile construction costs excluding project support costs( 5) Costs for terminal joint at $ 9,000 per lane should be applied in addition to lane replacment cost. Lane replacement costs are per lane- mile and terminal joint cost are per lane. ( 6) Punchout Repair A involves significant punchout repairs and 0.15' of flexible overlay. Itapplies to continuously reinforced concrete pavements that had previous punchout repairs and a flexible overlay. ( 7) Punchout Repair B involves moderate punchout repairs and 0.15' of flexible overlay. Itapplies to continuously reinforced concrete pavements where the totoal number of current and previous punchout repairs exceed 4 per mile. ( 8) Punchout Repair C involves minor punchout repairs and 0.15' of flexible overlay. Itapplies to continuously reinforced concrete pavements that where the totoal number of current and previous punchout repairs do not exceed 4 per mile.
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Table 5b. Estimated Construction Costs of Typical M& R Strategies for Rigid & Composite Pavements Flexible Overlay w/ Slab Replacements( FO+ JPCP SR, RSC of 12- Hour Curing Time) 215,000Flexible Overlay w/ Slab Replacements( FO+ JPCP SR, RSC of 4- Hour Curing Time) 233,000Mill, Slab Replacement & Overlay ( MSRO, RSC of 12- Hour Curing Time) 234,000Mill, Slab Replacement & Overlay ( MSRO, RSC of 4- Hour Curing Time) 252,000Mill, Slab Replacement & Overlay ( MSRO, RSC of 12- Hour Curing Time) 260,000Mill, Slab Replacement & Overlay ( MSRO, RSC of 4- Hour Curing Time) 280,00010251,00020279,00020941,000401,255,000202,011,000402,349,000202,482,000402,821,000201,493,000401,752,000201,854,000402,1 3,000201,951,000402,289,000202,422,000402,761,000$/ Lane- Mile( 4) Final Pavement TypePvmt. Design Life ( years) Future M& R Activity DescriptionLane Replacement with composite( with RSC of 12- Hour Curing Time) 20Lane Replacement( with RSC of 12- Hour Curing Time) Lane Replacement( with RSC of 4- Hour Curing Time) Lane Replacement( with RSC of 12- Hour Curing Time) Rigid - Jointed Plain Concrete Pavement ( JPCP) RehabilitationLane Replacement with composite( with RSC of 4- Hour Curing Time) Lane Replace with FlexibleCrack, Seat, & Flexible Overlay ( CSFOL) 1010Flexible / CompositeLane Replacement( with RSC of 4- Hour Curing Time) Rigid - Continuously Reinforced Concrete Pavement ( CRCP)
Notes:
See Table 5a.
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The following steps describe how the construction costs in Tables 4 and 5 can be used to estimate the costs of future rehabilitation activities:
1)
Find the applicable pavement M& R schedule for the project alternative being considered ( as described in Section 2.4).
2)
From the M& R schedule, identify the sequence of future rehabilitation activities that will take place through the entire analysis period.
3)
For each of the future rehabilitation activities shown in the M& R schedule sequence, find the description that best fits each activity by selecting the appropriate project type, the final pavement surface type, the design life, and the future M& R activity in Tables 4, 5a, or 5b ( Note: in most cases there will be more than one choice that will require exploration).
4)
Determine the applicable lane- mile cost for each future rehabilitation activity in Table 4, 5a, or 5b as follows:
( a)
Multiply the total number of project lane- miles by the lane- mile cost to get the construction cost for the future rehabilitation activity;
( b)
Determine the project support cost multiplier from Table 3 that is applicable to the calculated construction cost;
( c)
Multiply the calculated construction cost by the project support cost multiplier to get the project support cost for the future rehabilitation activity;
( d)
Add the construction cost and the project support cost to get the rehabilitation cost (“ Agency Construction Cost”).
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Example 2.3:
Determine the cost for future rehabilitation activities which will occur after implementing the project alternative described below:
CAPM w/ o right- of- way acquisition ( HMA Overlay)
•
40.0 lane- miles ( i. e., total project lane- miles including turn, auxiliary lane- miles) of an existing flexible pavement
•
Initial Agency Construction Cost: $ 4.6 million ($ 4.0 million for construction and $ 0.6 million for project support)
•
Analysis Period: 20 years.
•
Climate: Coastal
•
Maintenance Service Level: 1
Solution:
1)
Find the applicable pavement M& R schedule ( from Appendix 4, Table F- 1) Final Surface Type Pvmt Design Life Maint. Service Level CAPM Activity Service Life ( years) Annual Maint. Cost ($/ lane- mile) 51,100106,1005 1,100Activity Service Life ( years) Annual Maint. Cost ($/ lane- mile) 106,200106,100 Rehab HMA ( 10 yr) CAPM HMA Year 10 15Begin Alternative Construction5Year of ActionCAPM HMAHMA 5+ 1,2 3 CAPM HMAActivity DescriptionYear of ActionActivity Description010 0CAPM HMA515
2)
Identify the prescribed sequence of future rehabilitation activities after initial construction ( within the 20- year analysis period)
( a)
10- year Rehab HMA in Year 5
( b)
CAPM in Year 15
3)
Applicable M& R alternative for each future rehabilitation activity ( from Table 4)
( Note: solution shows that after initial construction the engineer will have a choice
of future rehabilitation activities. The solution for both is shown below)
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( a)
10- year Rehab HMA in Year 5:
•
HMA Overlay
•
HMA Mill and Overlay
( b)
CAPM in Year 15:
•
HMA Overlay
•
HMA Mill and Overlay
4)
Lane- mile costs of future rehabilitation activities ( from Table 4)
( a)
10- year Rehab in Year 5:
•
HMA Overlay = $ 299,000/ lane- mile
•
HMA Mill and Overlay = $ 318,000/ lane- mile
( b)
CAPM in Year 15: not applicable [ Note: it is assumed that the rehabilitation costs would be same as the agency construction cost for the initial construction ($ 4,000K)]
•
HMA Overlay = Assume same as initial construction ($ 4 million)
•
HMA Mill and Overlay $ 118,000/ lane- mile
5)
Construction costs for future rehabilitation activities
( a)
10- year Rehab in Year 5:
•
HMA Overlay = $ 299,000/ lane- mile X 40 = $ 11,960,000
•
HMA Mill and Overlay = $ 318,000/ lane- mile X 40 = $ 12,720,000
( b)
5- year CAPM in Year 15:
•
HMA Overlay = $ 4,000,000
•
HMA Mill and Overlay = $ 118,000/ lane- mile X 40 = $ 4,720,000
6)
Project support cost multipliers for future rehabilitation activities ( from Table 3)
( a)
10- year Rehab in Year 5:
•
0.19 ( for rehabilitations over $ 5 million w/ o right- of- way)
( b)
5- year CAPM in Year 15:
•
0.15 ( for CAPM’s over $ 2 million w/ o right- of- way)
7)
Project support costs for future rehabilitation activities
( a)
10- year Rehab in Year 5:
•
HMA Overlay = $ 11,960,000 X 0.19 = $ 2,272,400
•
HMA Mill and Overlay = $ 12,720,000 X 0.19 = $ 2,416,800
( b)
CAPM in Year 15: $ 600K
•
HMA Overlay = $ 4,000,000 X 0.15 = $ 600,000
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Life Cycle Cost Analysis Procedures Manual November, 2007
•
HMA Mill and Overlay = $ 4,720,000 X 0.15 = $ 708,000
8)
Agency construction costs for the initial construction and future rehabilitation activities
( a)
CAPM Initial Construction ( Year 0):
•
Agency Construction Cost : 4,600,000 ($ 4,000K + $ 600K)
•
Agency Maintenance Cost: $ 1,100/ lane- mile x 40 lane- miles = $ 44,000
( b)
10- year Rehab in Year 5:
•
Agency Construction Cost:
o
HMA overlay = $ 11,960,000 + $ 2,272,000 = $ 14,232,000
o
HMA Mill & Overlay = $ 12,720,000 + $ 2,416,800 = $ 14,232,000 = $ 15,136,000
•
Agency Maintenance Cost: $ 6,100/ lane- mile x 40 lane- miles = $ 244,000
( c)
CAPM in Year 15:
•
Agency Construction Cost
o
HMA Overlay = Same as CAPM in Year 0 = 4,600,000 ($ 4,000K + $ 600K)
o
HMA Mill & Overlay = $ 4,720,000 + $ 708,000 = $ 5,428,000
•
Agency Maintenance Cost: $ 1,100/ lane- mile x 40 lane- miles = $ 44,000
2.5.4 User Costs
Best- practice LCCA calls for consideration of not only agency costs, but also costs to facility users. User costs include travel time costs and vehicle operating costs ( excluding routine maintenance) incurred by the traveling public. User costs arise when work zones restrict the normal flow of the facility and increase the travel time of the user by generating queues or formal or informal detours. User costs are also incurred during normal operations, but they are not considered in LCCA because normal travel costs are not dependent on individual project alternatives. Additional user costs resulting from work zones can become a significant factor when a large queue occurs in a given alternative.
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2.5.5 Remaining Service Life Value
If an activity has a service life that exceeds the analysis period, the difference is known as the Remaining Service Life Value ( RSV). Any rehabilitation activities ( including the initial construction) except for the last rehabilitation activity within the AP will not have a RSV. The RSV of a project alternative at the end of the analysis period is calculated by prorating the total construction cost ( agency and user costs) of the last scheduled rehabilitation activity.
2.6 Calculating Life- Cycle Costs
Calculating life- cycle costs involves direct comparison of the total life- cycle costs of each alternative. However, dollars spent at different times have different present values, the anticipated costs of future rehabilitation activities for each alternative need to be converted to their value at a common point in time. This is an economic concept known as “ discounting.”
A number of techniques based upon the concept of discounting are available. FHWA recommends the present value ( PV) approach, which brings initial and future costs to a single point in time, usually the present or the time of the first cost outlay. The equation to discount future costs to PV is:
niFPV) 1( 1+ = ( Equation 1)
Where:
F = future cost at the end of nth years
i = discount rate
n = number of years
However, the equivalent uniform annual cost ( EUAC) approach is also used nationally. It produces the yearly costs of an alternative as if they occurred uniformly throughout the analysis period. The PV of this stream of EUAC is the same as the PV of the actual cost stream. Whether
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PV or EUAC is used, the decision supported by the analysis will be same. Caltrans requires the LCCA results to be documented using the present value approach. 36
Life Cycle Cost Analysis Procedures Manual November, 2007
CHAPTER 3 - USING REALCOST
3.1 Methodology
1.
Gather project information:
Gather as much project information as possible, such as:
•
Existing project type
•
Remaining Service Life of Existing pavement ( for widenings)
•
Project location
•
Project Scope
•
Potential final pavement type
•
Expected construction year
•
Construction scheme such as staging, direction, construction windows, etc.
•
Traffic information
2.
Select design alternatives.
Use the suggested alternatives in Table 1 or the preferred methodology followed by your district for selecting design alternatives. However, selection of project alternatives must follow the requirements specified in Section 2.1 of this manual.
After selecting the competing alternatives, estimate the costs associated with each of the alternatives ( Engineer’s estimate).
3.
Determine the “ Analysis Period.”
Once the alternatives are selected, use Table 2 ( see Section 2.2) to determine the appropriate analysis period. When analyzing three or more alternatives, determine the analysis period using the longest design life.
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4.
Determine the traffic inputs.
•
AADT for construction year
•
Single Unit truck percentage
•
Combination Trucks percentage
•
Normal operating speed for the project location
•
Number of lanes open under normal conditions. Section 3.3.3 of this manual shows how to obtain the information required to determine this inputs.
5.
Determine the traffic flow information.
Use Table 6 to determine the traffic flow inputs for RealCost. Traffic flow inputs include:
•
Free Flow Capacity of the facility
•
Queue Dissipation Capacity of Work Zone
•
Expected or maximum queue length,
6.
Enter the “ Project- Level Inputs” into RealCost.
7.
Determine the future rehabilitation sequence.
For each alternative, select the appropriate M& R schedule from Appendix 4. Section 2.4 shows the process for selecting the M& R Schedule and determining the future rehabilitation sequence.
8.
Determine the future rehabilitation cost. There is a cost associated with each of the future rehabilitation activities in the sequence. See Section 2.5 for information on how to determine these costs.
9.
Determine the “ Agency Maintenance Cost" from the appropriate M& R table.
10.
Determine the “ Work Zone Duration.”
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11.
For each of the alternatives, determine the Work Zone Duration ( WZD) for each future rehabilitation activity in the sequence. Use Table 8 or 9 as shown in Section 3.3.2
12.
Enter the “ Alternative- Level Inputs.”
13.
Evaluate the results.
Note that if the project is evaluating more than two alternatives, a separate accounting of RealCost will need to be developed in order to compare all the alternatives.
3.2 Installing & Starting RealCost
3.2.1 Installation
In order to prepare a life- cycle cost estimate using RealCost ( Version 2.2.1 California Edition), the software must first be installed. The software can be downloaded from: http:// www. dot. ca. gov/ hq/ esc/ Translab/ OPD/ DivisionofDesign- LCCA. htm. Follow the installation instructions provided on the website.
Note:
Because RealCost is an add- on program designed to run in Microsoft Excel 2000 ( or later), it should not require installation by Caltrans’ IT staff.
3.2.2 Start Up
Select “ RealCost 2.2” from the Windows “ Start Menu” ( Programs > RealCost > RealCost 2.2) to launch the program.
When prompted by Excel, choose “ Enable Macros” to run RealCost. Immediately after the worksheet appears, the “ Switchboard” panel opens on top of it ( see Figure 3- 1). If the switchboard does not appear, go to the “ Tools” drop down menu, select “ Macro,” and change the security to medium.
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Note:
The program allows you to input data either through the “ Switchboard” or directly into the Input Worksheet. This manual contains instructions for entering information by using the “ Switchboard”. To input values directly into the Input Worksheet, close the “ Switchboard” by clicking the “ X” in the upper right- hand corner. To restore it later, click “ RealCost” drop down menu at the top of the Excel window, and select “ RealCost Switchboard.”
Figure 3- 1: RealCost Switchboard
The “ Switchboard” consists of five sections ( See Figure 3- 1):
•
Project- Level Inputs;
•
Alternative- Level Inputs;
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Life Cycle Cost Analysis Procedures Manual November, 2007
•
Input Warnings;
•
Simulation and Outputs;
•
Administrative Functions.
These items are discussed in Sections 3.3 through Section 3.6
Note:
Most of the functions available from the “ Switchboard” are also accessible by selecting the “ RealCost” drop down menu in the Microsoft Excel menu bar.
3.3 Project Inputs
RealCost requires two levels of information. The first, “ Project- Level Inputs,” which are discussed in Section 3.3.1, are project- level data that apply to all the alternatives being considered for the project. The second information level, “ Alternative- Level Inputs” ( discussed in Section 3.3.2), is data that defines the differences between project alternatives ( e. g., agency costs and work zone specifics for each alternative’s component activities). To emphasize the differences between the two types of inputs, RealCost requires that they are entered separately.
3.3.1 Project Details
The “ Project Details” panel ( Figure 3- 2) is used to enter the project information details. Note that other than the “ Mileposts,” information entered here will not be used in the analysis. The information entered in here is used to identify and differentiate between projects. Once all the project documentation details are entered, click the “ Ok” button to return to the “ Switchboard” or the “ Cancel” button to start over.
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Figure 3- 2: Project Details Panel
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3
The “ Analysis Options” panel ( Figu
applied in the analysis of the project alternatives. This panel is where the actual analysis input for the project begins. The data inputs and analysis options available on this Panel are detailed below. • Analysis Units: Select either “ English” or “ Metric” to set the units to be used in the
a
nalysis. • Analysis P
a
lternatives will be compared. Refer to Figure 2- 1 and Table 2 in Section 2- 2, “ AnaPeriod,” to decide on the appropriate analysis period that will be common to all competing alternatives in the project. • Discount Rate (%): Enter the Caltrans
a
nalysis. • Beginning
a
lternative is expected to begin. This is the same as the construction year ADT fouthe design designation or traffic projections for the project ( see Figure 3- 4 from HDM Index 103.1). This should be the same year as the initial construction year AADT fromthe design designation If the project did not require a design designation ( i. e. traffic projections) or traffic projections were not done, use the year you expect the project end construction.
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Life Cycle Cost Analysis Procedures Manual November, 2007
•
Include Agency Cost Remaining Service Life Value: Select the checkbox for RealCost to automatically calculate and include the prorated share of the agency cost of the last future rehabilitation activity if it extends beyond the analysis period.
•
Include User Costs in Analysis: Select the checkbox to have RealCost include user costs ( see Section 2.5) in the analysis and display the calculated user costs results.
•
User Cost Computation Method: Select “ Calculated” to have RealCost calculate user costs based on project- specific input data.
Note:
As an option, CA4PRS can be used to calculate the user costs for the life- cycle cost analysis. CA4PRS ( Rapid Rehab Software) is software developed by Caltrans and others to compare the impacts on construction schedules and the traveling public of various traffic management alternatives. One of the outputs from the program is user costs. The program is currently limited on what options it can investigate but is being expanded as resources allow. The latest version of CA4PRS and the user manual can be obtained from the Division of Research and Innovation website at:
http:// www. dot. ca. gov/ research/ roadway/ ca4prs/ ca4prs. htm
If CA4PRS data is used, analyses will be needed for all of the initial construction options and future rehabilitation options. If CA4PRS generated data is used, select “ Specified” under “ User Cost Computation Method”.
•
Traffic Direction: Directs RealCost to calculate user costs for the “ Inbound” lanes, the “ Outbound” lanes, or “ Both” lanes. Select the traffic direction that will be affected by work zone operations. “ Inbound” is used for the direction where traffic peaks in the AM hours. “ Outbound” is used for the direction where traffic peaks in the PM hours. “ Both” is used when construction is occurring in both directions.
•
User Cost Remaining Service Life Value ( RSLV): Select the checkbox to have RealCost include the user RSLV of a project alternative Once all the analysis options are defined, click the “ Ok” button to return to the “ Switchboard”.
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3.3.3 Traffic Data
The “ Traffic Data” panel ( Figure 3- 5) is used to enter project- specific traffic data that will be used exclusively to calculate work zone user costs in accordance with the method outlined in the FHWA’s LCCA Technical Bulletin ( 1998) and “ Life- Cycle Cost Analysis in Pavement Design.”
Traffic data are developed for PIDs and PRs when pavement work is involved. Some of the data for the “ Traffic Data” panel can be found in the design designation ( Figure 3- 4), traffic projections generated for the specific project, or from the Division of Traffic Operations website ( http:// www. dot. ca. gov/ hq/ traffops/ saferesr/ trafdata/ index. htm).
Figure 3- 5: Traffic Data Panel
•
AADT Construction Year ( total for both directions): Enter the annual average daily traffic ( AADT) total for both directions in the beginning year of the analysis. This is
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Life Cycle Cost Analysis Procedures Manual November, 2007
the same as the construction year ADT found in the design designation or traffic projections for the project ( see HDM Index 103.1 and Figure 3- 4). For an example of what to do if a design designation or traffic forecast was not developed for the project, see Appendix 6.
•
Single Unit Trucks as Percentage of AADT (%): Enter the percentage of the AADT that is single unit trucks ( i. e., commercial trucks with two- axles and four tires or more) by doing the following:
Figure 3- 6: Traffic Information
Go to the Division of Traffic Operations Traffic Data Branch website ( http:// www. dot. ca. gov/ hq/ traffops/ saferesr/ trafdata/ index. htm) and find the most current file of “ Annual Average Daily Truck Traffic” data available ( see Figure 3- 6). Find the “% Truck AADT” for 2- axle trucks at the project location. There may be several values given within the limits of the project. Choose the one that best represents the overall project, use the average or the weighted average. Obtain the truck traffic volume ( T) from the design designation ( HDM Topic 103.1, Figure 3- 4). This value is measured as a percentage. If there is no design designation, use the Total Trucks % value from the Division of Traffic Operations web site referred to above ( Use selection process similar to the one used for 2- axle truck).
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Note:
The total truck volume in the design designation does not need to match the total truck percentage on the Division of Traffic Operations website. If there is a wide disparity in values between the two numbers, the designer should review the accuracy of the traffic projections in the design designation and have the design designation updated if necessary.
Using Equation 2 to calculate the “ Single Unit Trucks as Percentage of AADT (%)” ( Assumption: “ Total Trucks %” and “ Single Unit Trucks %” will remain the same in future years): ) 100( TATSUT×= ( Equation 2)
where:
SUT = Single Unit Trucks as Percentage of AADT (%)
T = Truck Traffic Volume (% of AADT Total).
TA = 2- Axle Percent ( percentage of Truck AADT Total).
Example 3.1:
Given:
Total Trucks % = 6.22%
2- Axle Percent = 33.93%
Find:
The Single Unit Trucks as Percentage of AADT
Using Equation 2, the Single Unit Trucks as Percentage of AADT (%) is % ( or 2.1, but be consistent)
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Life Cycle Cost Analysis Procedures Manual November, 2007
•
Combination Trucks as Percentage of AADT (%): Enter the percentage of the AADT that is combination trucks ( i. e., trucks with three axles or more). This value is obtained by subtracting the “ Single Unit Trucks as Percentage of AADT (%)” from the “ Total Trucks % ( percentage of AADT Total).”
•
Annual Growth Rate of Traffic (%): Enter the percentage by which the AADT in both directions will increase each year. Contact the Division of Traffic System Information for the “ Annual Growth Rate of Traffic” or calculate the approximate value with the available AADT values ( in the most current and future years) using the following equation: 100] 1)[( ) 1( ×−=− CYFYCTFTA ( Equation 3)
where:
A = Annual Growth Rate of Traffic
FT = Future Year AADT ( total for both directions) obtained from the project design designation ( HDM 103.1)
CT = Most Current Year AADT ( total for both directions) obtained from the project design designation ( HDM 103.1)
FY = Future Year in which AADT is available
CY = Most Current Year in which AADT is available.
Example3.2:
Given:
Future Year AADT ( total for both directions) = 18,000 ( year 2025)
Most Current Year AADT ( total for both directions) = 9,800 ( year 2005)
The Annual Growth Rate of Traffic is:
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•
Speed Limit under Normal Operating Conditions ( mph): Enter the posted speed limit at the project location. If a roadway is being newly built, enter an anticipated speed limit based on traffic laws. District Traffic Operations can provide a recommendation if needed.
•
Lanes Open in Each Direction under Normal Conditions: Enter the number of lanes open to traffic in each direction under normal operating conditions of the facility. For new construction and/ or widening of an existing roadway, enter the number of lanes1 that will open after completing the initial construction.
•
Free Flow Capacity ( vphpl): Enter the number of vehicles per hour per lane ( vphph) under normal operating conditions. Table 6 provides typical values for standard lane and shoulder widths for various types of terrain. If there are nonstandard lane and shoulder widths or if it is desired to get a more specific free flow capacity, click the “ Free Flow Capacity Calculator” in RealCost ( see Figure 3- 5) to open a panel that calculates free flow capacities based upon the Highway Capacity Manual ( 1994, 3rd Ed.). To use the calculator, the following project- specific information is needed: number of lanes in each direction, lane width, proportion of trucks and buses ( for state highways use % of trucks only), upgrade, upgrade length ( for multiple slopes use the average grade throughout the project), obstruction on two sides, and distance to obstruction/ shoulder width ( Where the existing shoulder width is unknown, use the standard shoulder width as the input).
Note:
An alternate procedure for estimating “ Free Flow Capacity” can be found in Appendix 5.
1 Using the ultimate lane configuration and entering a “ Work Zone Duration” (“ Alternative 1,” Figure 3- 10) of zero for the initial construction of each new construction or widening alternative will generate acceptable results of the analysis of future rehabilitation activities.
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Table 6. Traffic Input Values Type of TerrainLevelRollingMountainousLevelRollingMountainousFree Flow Capacity ( vphpl) 1,6201,4801,2602,1701,9501,620Queue Dissipation Capacity ( vphpl) 1,7101,5701,3301,7001,5301,270Maximum AADT Per Lane 40,95537,39031,85053,77348,30540,140Work Zone Capacity ( vphpl)( 1) 1,0509608201,5101,3601,130Maximum Queue LengthNotes: * Refer to the calculation procedures included in Appendix 5, " Traffic Inputs Estimation". ( 1) Assumed one lane to be open for traffic in single- lane highways and two or more lanes to be open for traffic in multi- lane highways. Two- Lane HighwaysMulti- Lane Highways7.0 miles if the estimated maximum queue length is longer than 7.0 miles5.0 miles if the estimated maximum queue length is longer than 5.0 miles
•
Queue Dissipation Capacity ( vphpl): Enter the vehicles per hour per lane capacity of each lane during queue- dissipation operating conditions. Table 6 provides values for typical two- lane and multi- lane ( in each direction) highways. As an alternative, estimate the queue dissipation capacity using the procedures for “ Queue Dissipation Capacity” in Appendix 5.
•
Maximum AADT ( total for both directions): Enter the maximum AADT ( total for both directions) at which the traffic growth will be capped. This value recognizes that there is only so much traffic that can be placed on a roadway in a 24- hour period. Table 6 provides recommended per lane values for typical two- lane and multi- lane highways. As an alternative, the volume may be estimated using the procedures for “ Maximum AADT” in Appendix 5.
•
Maximum Queue Length ( miles): Enter a practical maximum length of queue in miles. Reasonable maximum queue length could be one or two exits prior to the work zone or an exit that leads to a reasonable alternate route. Queue- related user costs, which are based upon queue length, will be calculated with this value in cases when
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the RealCost- calculated queue lengths exceed this value. If a project- specific value is not available, enter seven ( 7) miles for two- lane highways and five ( 5) miles for multi- lane highways respectively.
Note:
Appendix 5 provides an explanation on the demand- capacity model – queuing theory – that RealCost uses in calculating maximum queue length.
•
Rural or Urban Hourly Traffic Distribution: Select “ Rural” or “ Urban” depending on the project location. For details on Caltrans roadway classifications, visit the Division of Traffic System Information website at http:// www. dot. ca. gov/ hq/ tsip/ hpms/ Page1. php.
Once all the traffic data has been input, click the “ Ok” button to return to the Switchboard or the “ Cancel” button to start over.
3.3.4 Value of User Time
The “ Value of User Time” panel ( Figure 3- 7) is used to enter the estimated cost applied to an hour of user time. The dollar value of user time can be different for each type of vehicle and is used to calculate user costs associated with delay during work zone operations. Enter the following default values:
•
$ 10.46 per hour for passenger cars.
•
$ 27.83 per hour for single unit trucks.
•
$ 27.83 per hour for combination trucks.
These dollar values are based on the Caltrans’ Cal- B/ C model ( 2004). Once the dollar values have been entered, click the “ Ok” button to return to the “ Switchboard” or click the “ Cancel” button to start over.
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Figure 3- 7: Value of User Time Panel
3.3.5 Traffic Hourly Distribution
The “ Traffic Hourly Distribution” Panel ( Figure 3- 8) allows adjustment to ( or restoration of) the default values for rural and urban traffic, which are used in converting AADT to an hourly traffic distribution. If project- specific data is not available, use the California weekday ( Monday through Friday) default values ( Figure 3- 8). Select the “ Traffic Hourly Distribution” button on the RealCost Switchboard ( Figure 3- 1) to see the default values. These defult values were generated from Caltrans traffic count data ( April 2005 data by the Division of Traffic Operations) at selected highway locations and can be used for any location in the State.
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Figure 3- 8: Traffic Hourly Distribution Panel with California Weekday Default Values
Note:
Currently the program only contains data for weekday “ Traffic Hourly Distribution” which will not fit alternatives that use weekend closures. Efforts are currently underway to add a weekend “ Traffic Hourly Distribution” to the program. Until the weekend data is included, alternatives that use weekend closures will need to be run separately from the other alternatives and weekend “ Traffic Hourly Distribution” data will need to be entered manually. California default weekend “ Traffic Hourly Distribution” data can be found in Appendix 7.
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3.3.6 Added Time and Vehicle Stopping Costs
The “ Added Time and Vehicle Stopping Costs” panel ( Figure 3- 9) is used to adjust the default values for added time and added cost per 1,000 stops. The default values are based upon the National Cooperative Highway Research Program ( NCHRP) Study 133 ( 1996), Procedures for Estimating Highway User Costs, Air Pollution, and Noise Effects. These values are used to calculate user delay and vehicle costs due to speed changes that occur during work zone operations. The “ Idling Cost per Veh- Hr ($)” is used to calculate the additional vehicle operating costs that result from moving through a traffic queue under stop- and- go conditions.
Figure 3- 9: Added Time and Vehicle Stopping Costs Panel
The default values, expressed in 1996 dollars, are adjusted to the current year dollar amounts by entering the current year and the associated transportation- component Consumer Price Index
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( CPI). The current year will be the year when construction is expected to begin. Table 7 shows the transportation- component CPI’s collected and projected by the California Department of Finance. Since the statewide transportation- component CPI’s are not available yet, the U. S. transportation- component CPI’s ( in bold text) can be used. The values for specific areas like Los Angeles ( LA) and San Francisco ( SF) can be used for those specific areas.
Example 3.3:
For a 2006 year analysis:
Enter “ 2006” for “ Current Year” and “ 178.0” for “ Current Transp. Component CPI”
Click the “ Escalate” button ( see Figure 3- 9).
The program will update the cost data. To get back to the default values, click the “ Restore Defaults” button.
Note: 1996 is the default base year.
Table 7. Transportation Component Consumer Price Indexes
YearUSLA CMSA( 1) SF CMSA( 2) 1996143.0144.3133.51997144.3145.2133.61998141.6142.6132.01999144.4146.8135.82000153.3154.2143.12001154.3155.3143.72002152.9154. 141.02003157.6160.3145.02004163.1166.5149.62005175.2176.2157.32006178.0177.1159.32007177.2171.6156.22008 & beyond177.9167.3154.1 http:// www. dof. ca. gov/ HTML/ FS_ DATA/ LatestEconData/ FS_ Price. htm( 2) SF CMSA ( Consolidated Metropolitan Statistical Area): includes counties of Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Santa Cruz, Solano, & Sonoma Orange, Riverside, San Bernadino, & Ventura( 1) LA CMSA ( Consolidated Metropolitan Statistical Area): includes counties of Los Angeles, * Source: California Department of Finance, Economic Research UnitNotes:
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3.3.7 Save Project- Level Inputs
To save the project level inputs file, go back to the RealCost Switchboard ( Figure 3- 1) and select the “ Save Project- Level Inputs” button. RealCost will save the project- level inputs at the preferred location specified by the user with the user- specified name. The project input file will be automatically saved with a *. LCC extension. To retrieve the file later, select the “ Open Project Level Inputs” button located on the Switchboard.
Note:
Saving the project- level inputs does not make any changes made to default data in “ Traffic Hourly Distribution” or “ Added Time and Vehicle Stopping Costs.” Any of this project- specific data must be reentered when reopening RealCost. If required, use “ Save LCCA workbook as” button to save all modified level inputs.
3.3.8 Alternative- Level Inputs
The “ Alternative 1” and “ Alternative 2” ( Figure 3- 10) panels are identical and are used to input information for the project alternatives being analyzed Each project alternative can include up to six future rehabilitation activities (“ Rehabilitation 1” through “ Rehabilitation 6, see Figure 3- 10”) after the initial construction ( i. e., project alternative). The data describing these activities must be entered sequentially according to the pavement M& R schedule associated with for each project alternative. For example, “ Initial Construction” precedes “ Rehabilitation 1” and “ Rehabilitation 3” precedes “ Rehabilitation 4, etc.”
Note:
Because many projects will need at least 3 alternatives analyzed to meet the alternative requirements in Section 2.1 and the program currently can only analyze two alternatives at a time, multiple runs of the program will be needed to cover all the needed alternatives. Caltrans is currently working with FHWA to expand the number of alternatives that can be analyzed at once in the program. 56
Life Cycle Cost Analysis Procedures Manual November, 2007
Figure 3- 10: Typical Alternative Panel ( Alternative 1 shown)
The data inputs required under each activity tab on the panel are described below.
DESCRIPTION
•
Alternative Description: Enter a description for the project alternative such as “ 20- year Rehab ( HMA Overlay).”
•
Activity Description: Enter a description for the initial construction or future rehabilitation activities being considered for each project alternative. For Initial Construction, the activity description will be the same as the alternative description.
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ACTIVITY COST AND SERVICE LIFE INPUTS
•
Agency Construction Cost ($ 1000): Under the “ Initial Construction” tab, enter the total initial cost in thousands of dollars ( engineer’s estimate plus project support costs) for a project alternative ( see Section 2.5.1, “ Initial Costs”). For future rehabilitation activities after the initial construction ( project alternative), enter the total rehabilitation costs ( construction cost from table 4 or 5 plus support cost) in thousands of dollars for each future rehabilitation activity ( see Section 2.5.3, “ Rehabilitation Costs”).
•
Activity Service Life ( years): Enter the activity service life of initial construction or that of future rehabilitation activity to be followed. Refer to Appendix 4 for the appropriate pavement M& R schedule that shows the activity service lives estimated for the initial construction and the future rehabilitation activities to be implemented for each project alternative ( see the example in Section 2.5.3, “ Rehabilitation Costs”).
•
User Work Zone Costs ($ 1000): This field is inaccessible because the “ User Cost Computation Method” in the “ Analysis Options” panel ( Figure 3- 3) is set to “ Calculated”. If this is not the case, go to “ Analysis Options” panel to modify the “ User Cost Computation Method.”
•
Maintenance Frequency ( years): This input refers to the cyclical frequency of interim, preventive, corrective, and routine maintenance treatments to follow after the initial construction or after each future rehabilitation activities. Enter one ( 1) year as the “ Maintenance Frequency,” because the cost of the maintenance treatments shown in the M& R schedules have been annualized ( see Section 2.5.2).
•
Agency Maintenance Cost ($ 1000): As discussed in Section 2.5.2, “ Maintenance Costs,” this includes the costs of preventive, corrective, and routine maintenance treatments to preserve or to extend the service life of initial construction and any future rehabilitation activities. See the example in Section 2.5.3, “ Rehabilitation Costs” for details on how to calculate this cost using the appropriate M& R schedule.
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ACTIVITY WORK ZONE INPUTS
•
Work Zone Length ( miles): This input refers to the length ( in miles) of the work zone being considered for initial construction and for each future rehabilitation activity. The work zone length should be based on what is allowed from the Traffic Management Plan ( TMP) for the initial construction or historical experience. Note that the Work Zone Length ( WZL) is not necessarily the full length of the project limits. It should be measured from beginning to end of the reduced speed area where the work zone speed limit will be in effect daily or nightly. Information and recommendations can be obtained from the District Construction and Traffic Operations if needed. Note that WZL can change from one activity to the next. If uncertain, consult the District Construction Unit or the DME regarding the WZL.
•
Work Zone Duration ( days): Refers to the number of days during which the work zone will be affecting traffic. For example, if the work zone is in effect five days a week for four weeks, the duration is twenty. Determine the Work Zone Duration ( WZD) using the following formula: PRmilesLaneWZD− = ( Equation 4)
WZD = Work Zone Duration PR = Productivity Rate
Note:
Several special cases to be aware of:
Continuous lane closures – If a lane is closed for the duration of the contract, it is treated as a 24- hour closure ( from hour 0 to hour 24) for each working day it is closed. Therefore, if the lane is closed for 3 months the total number of closures is 3 months times 21 work days per month, for a total of 63 days.
Weekend ( 55- hour) closures – multiply 2.3 (= 55/ 24) by the number of closures needed in order to get the number of days needed. This is necessary because the RealCost program can only analyze closures within a 24- hour period and weekend closures last for over 2 days.
Work not requiring a lane closure – In some instances, lanes can be detoured and work can be done behind K- rail or other separation from traffic. In this instance, if lanes do not need to be closed for work done behind the K- rail, the work zone duration ( for this work) is zero. 59
Life Cycle Cost Analysis Procedures Manual November, 2007
For initial construction, the work zone duration should be estimated as part of establishing the critical path method ( CPM) schedule for the project. Work Zone Duration is not the same as the number of working days used to build the project. WZD is the estimated number of days lane closures are necessary for project construction work. Use a WZD of zero1, for each of the competing alternatives, when the initial construction is a new construction or a widening. For future rehabilitations, the estimated work zone must be determined using the total length of pavement structure work ( lane- miles) and the corresponding productivity rate from Table 8 or Table 9 ( see Equation 4).
Tables 8 and 9 provide the estimates of work that can be completed during different construction windows ( nighttime closure, weekend closure, etc.) for typical M& R strategies for flexible pavements ( Table 8) and for rigid and composite pavements ( Table 9). These production rates are estimates developed using CA4PRS ( Construction Analysis for Pavement Rehabilitation Strategies) software and assuming typical working conditions and resource configurations observed in past projects.
Note:
The latest version of CA4PRS and the user manual can be obtained from the Division of Research and Innovation Web site at:
http:// www. dot. ca. gov/ research/ roadway/ ca4prs/ ca4prs. htm.
Relative to agency costs, user costs can have a major impact on the total life- cycle cost, so it is important to use the most cost effective traffic management practice possible. In some cases, such as when comparing flexible and rigid pavement strategies, the most cost effective traffic management plan may not be the same for all the alternatives ( initial and future rehabilitation) being considered. If the traffic management plan does not provide a strategy for the initial or future rehabilitation strategy or if the strategy needs to be checked to be sure it is the most cost effective, the designer can use the construction traffic analysis software CA4PRS ( freeways only) to analyze options or do the following quick check:
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1 Using a WZD = 0 for the initial construction of each new construction or widening alternative and entering the ultimate lane configuration in “ Lanes Open in Each Direction Under Normal Conditions” (“ Traffic Data,” Figure 3- 5) will generate acceptable results of the analysis of future rehabilitation activities.
.
1)
Use Equation 5 to calculate the number of closures needed to maximize work zone length with each construction window. PRMWZCN2max×= ( Equation 5)
CN max = No. of Closures needed for the Maximum
Work Zone Length
MWZ = Maximum Work Zone Length
PR = Production Rate ( lane- mile/ closure)
2)
Identify those construction windows whose CN max is larger than 1 ( Note: if CNmax of a particular construction window is less than 1, that traffic management strategy should not be evaluated further because is not realistic)
3)
Use Equation 6 to calculate the total closure time needed for the maximum work zone length,
CHCNCT×= maxmax ( Equation 6)
CT max = Total Closure Time Needed for the Maximum Work Zone Length
CN max = No. of Closures Needed for the Maximum Work Zone Length
CH = Closure Hours
4)
Identify the construction window with the lowest CT max. If this strategy is a plausible traffic management strategy, it can be used in lieu of the one in the traffic management plan for future rehabilitation activities.
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Note:
If the analysis is done and used for one alternative or future rehabilitation strategy it must be used for all alternatives and future rehabilitation strategies. This is necessary to assure that the answers from the analysis are consistent and comparable to each other.
•
Work Zone Capacity ( vphpl): Enter the vehicular capacity of one lane of the work zone for one hour. Table 6 provides values for typical two- lane and multi- lane highways. As an alternative, the capacity may be estimated using the procedures for “ Work Zone Capacity” in Appendix 5.
•
Work Zone Speed Limit ( mph): This is the expected operating speed within the work zone. Enter a speed that is 5 mph less than the posted speed limit unless there is an approved reduced speed limit for the project. Approved reductions in posted speed limits can be found in the traffic management plan.
•
No. of Lanes Open in Each Direction During Work Zone: Enter the number of lanes to be open when the work zone is in effect. The number of lanes to be open applies to each direction. This information can be obtained from the traffic management plan or District Traffic Operations.
•
Work Zone Hours: Enter the zone hours using a 24- hour clock ( from 0 to 24) during which the work zone is in effect. Work zone timing can be modeled separately for inbound and outbound traffic for up to three separate periods during each day. During these hours, road capacity is limited to the work zone capacity. Work zone hours can be obtained from the TMP or District Traffic Operations. If the traffic management plan includes variable work zone hours ( lane closures) for the project, use the hours that apply most often to the project as a whole.
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Table 8. Productivity Estimates of Typical Future Rehabilitation Strategies for Flexible Pavements 5 to 7- Hour Closure8 to 12- Hour Closure16 hour/ day Operation( 2) 24 hour/ day Operation( 3) 1,2,30.631.502.674.8315.13Mill & Overlay5+ 1,2,30.270.641.021.845.165+ 1,2,30.420.921.743.179.921,2,30.220.410.781.514.411,2,30.420.921.743.179.921,2,30.220.410.781.514.411,2,30.851.993.556.4220.121 2,30.290.791.242.236.211,2,30.321.162.083.7911.870.240.590.981.775.16101,2,30.280.701.412.728.57201,2,30.180.381.051.916.021,2, 0.140.370.481.093.261,2,30.060.260.250.752.19101,2,30.230.441.032.086.58201,2,30.160.500.631.534.96101,2,30.130.330.400.942.912 1,2,30.060.240.400.602.03101,2,30.230.441.032.086.58201,2,30.160.500.631.534.96101,2,30.130.330.400.942.91201,2,30.060.240.400. 02.031,2,30.631.502.674.8315.13201,2,30.420.921.743.179.921,2,30.270.641.021.845.161,2,30.180.310.651.303.771,2,30.420.921.743. 79.921,2,30.320.641.262.347.391,2,30.220.410.781.514.41201,2,30.160.370.541.123.32RehabilitationRAC- GOverlay RAC- G w/ RAC- O1,2,35+ Mill & Overlay5+ 5+ 205+ 10Mill & Overlay5+ 5+ 1020Mill & OverlayHMA w/ OGFCOverlay Overlay HMA w/ RACOverlay Overlay HMA w/ OGFC101020Overlay RAC- Gw/ RAC- OMill & OverlayRAC- GOverlay HMAMill & OverlayMill & OverlayHMAPvmt Design Life ( years) 5+ CAPM Average Lane- mile Completed Per Closure( 1) Weekend Closure( 4) ( 55- Hour) Continuous ClosureMill & OverlayHMA w/ RACOverlay Overlay Mill & Overlay10Future M& R AlternativeMaint. Service LevelFinal Surface TypeMill & Overlay5+ Overlay Daily Closure ( Weekday)
Notes: UD - Under Development. See Office of Pavement Design for Assistance* Refer to Appendix 1, " Glossary and List of Acronyms" for definitions of terms used in the table. * Refer to Appendix 3 for a expanded version of the table. ( 1) Production rates in this table are based on representative assumptions that are applied consistantly throughout the table. These rates are only for calculating calculating future user costs using the procedures in this manual and not for any other purpose. More project specific user costs for some freeway situations can be obtained from the CA4PRS software. ( 2) 24- hour continuous closure with 16 hours of operation per day( 3) 24- hour continuous closure with 24 hours of operation per day( 4) 55- hour extended closure over the weekend
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Table 9. Productivity Estimates of Typical Future Rehabilitation for Rigid and Composite Pavements
5 to 7- Hour Closure10- Hour Closure16 hour/ day Operation( 2) 24 hour/ day Operation( 3) Flexible Overlay5+ 1,2,30.851.993.556.4220.124- hr RSC0.311.552.9112- hr RSC1.474.4516.194- hr RSC0.142.004.5712- hr RSC0.714.1423.714- hr RSC0.202.806.4012- hr RSC1.005.8033.204- hr RSC0.507.0016.0012- hr RSC2.5014.5083.004- hr RSC0.372.121.4812- hr RSC1.114.7224.014- hr RSC0.130.841.6012- hr RSC0.682.328.884- hr RSC5+ 0.507.0016.0012- hr RSC2.5014.5083.00Flexible Overlay w/ Slab Replacement ( FO + JPCP SR) 4- hr RSC0.130.841.60Flexible Overlay w/ Slab Replacement ( FO + JPCP SR) 12- hr RSC0.682.328.88Mill, Slab Replacement & Overlay ( MSRO) 4- hr RSC0.272.124.48Mill, Slab Replacement & Overlay ( MSRO) 12- hr RSC1.114.7224.01Mill, Slab Replacement & Overlay ( MSRO) 4- hr RSC0.192.014.25Mill, Slab Replacement & Overlay ( MSRO) 12- hr RSC0.884.3822.94100.280.701.412.728.57200.230.441.032.086.58200.100.400.671.233.95400.060.300.510.832.814- hr RSC0.010.040.1812- hr RSC0.100.130.604- hr RSC0.010.030.1512- hr RSC0.100.110.504- hr RSC0.020.090.1812- hr RSC0.120.160.704- hr RSC0.020.050.1612- hr RSC0.100.150.604- hr RSC0.010.030.1312- hr RSC0.080.110.504- hr RSC0.010.020.1212- hr RSC0.060.100.40Replace with CompositeRigid - Jointed Plain Concrete Pavement ( JPCP) Lane ReplacementRigid - Jointed Plain Concrete Pavement ( JPCP) Roadway Rehabilitation5+ 5+ Final Surface TypeMaint. Service LevelDaily Closure ( Weekday) Pvmt. Design Life ( years) Future M& R AlternativeConcrete Pavement Rehab A( 1) Concrete Pavement Rehab B( 2) Concrete Pavement Rehab C( 3) CAPM 5+ 5+ 5+ 1,2,31,2,31,2,3Flexible / Composite1,2,3Flexible Overlay w/ Slab Replacements ( FO + JPCP SR) Weekend Closure( 4) ( 55- Hour) Average Lane- mile Completed Per Closure( 1) Continuous ClosureRigid - Continuously Reinforced Concrete Pavement ( CRCP) Punchout Repairs A( 5) Punchout Repairs C( 6) Punchout Repairs C( 7) Flexible / Composite1,2,31,2,31,2,3Rigid - Continuously Reinforced Concrete Pavement ( CRCP) Lane Replacement4020401,2,3FO= Flexible Overlay JPCP = Jointed Plain Concrete Pavement SR = Slab Replacement RSC = Rapid Set Concrete CRCP = Continuosly Reinforced Concrete PavementCrack, Seat, & Flexible Overlay ( CSFOL) Replace with Flexible5+ 1010202040201,2,31,2,31,2,31,2,31,2,31,2,31,2,31,2,31,2,3Notes: UD - Under Development. See Office of Pavement Design for Assistance* Refer to Appendix 1, " Glossary and List of Acronyms" for definitions of terms used in the table. * Refer to Appendix 3 for a expanded version of the table. ( 1) Production rates are based on the lower end of the representative assumptions for the range and are applied consistantly throughout the table. These rates are only for calculating future user costs for the procedures in this manual and not for any other purpose. More project specific user costs for some freeway situations can be obtained from the CA4PRS software. ( 2) 24- hour continuous closure with 16 hours of operation per day( 3) 24- hour continuous closure with 24 hours of operation per day( 4) 55- hour extended closure over the weekend( 5) Punchout Repair A involves significant punchout repairs and 0.15' of flexible overlay. Itapplies to continuously reinforced concrete pavements that had previous punchout repairs and a flexible overlay. ( 6) Punchout Repair B involves moderate punchout repairs and 0.15' of flexible overlay. Itapplies to continuously reinforced concrete pavements where the totoal number of current and previous punchout repairs exceed 4 per mile. ( 7) Punchout Repair C involves minor punchout repairs and 0.15' of flexible overlay. Itapplies to continuously reinforced concrete pavements that
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Note:
For weekend closures, enter 0 to 24 on first period line.
Example 3.4:
Determine the “ Activity Work Zone Inputs” for future rehabilitation activities of the following project alternative:
CAPM ( HMA Overlay)
•
20.4 lane- miles ( project length 3.4 miles, 3 lanes in each direction, mainline only) of existing flexible pavement
•
Work Zone Duration ( days): 12 days based upon the following information from the traffic management plan or assumed:
( a)
Typical lane closure from 8 PM till 6 AM the next morning.
( b)
Single- lane paving with two lanes closed at one time.
( c)
Approximately 1.7 lane- miles will be overlaid during each closure
( d)
Work Zone Length of 1.4 miles for each closure
•
Initial Construction Year: same as the beginning year of the analysis period
•
Climate Region: South Coast
•
Analysis Period: 20 years.
•
Maintenance Service Level 2
Solution
1)
Find the applicable pavement M& R schedule for the project alternative being considered. ( from Appendix 4, Table F- 1)
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Life Cycle Cost Analysis Procedures Manual November, 2007
2)
Identify the future rehabilitation activities ( including CAPM and reconstruction) whose year of action falls before the end of analysis period ( 20 years for this example.)
( a)
10- year Rehab in Year 5
( b)
5- year CAPM in Year 15
3)
Find the applicable M& R alternative for each future rehabilitation activity (“ Future M& R Alternative” in Table 8 or 9). From Table 8 for the:
( a) 10- year Rehab in Year 5: HMA Overlay or Mill and Overlay;
( b) CAPM in Year 15: HMA Overlay or Mill and Overlay
4)
Find the applicable production rate estimate for each future rehabilitation activity ( from Table 8)
( a)
10- year Rehab in Year 5
•
10- year HMA Overlay ( 8- 12 hours): 0.70 lane- miles/ closure
•
10- year HMA Mill and Overlay ( 8- 12 hours): 0.37 lane- miles/ closure
( b)
5- year CAPM in Year 15: all the work zone inputs are assumed to be same as for initial construction
•
CAPM ( HMA Overlay): 1.50 lane- miles/ closure
•
CAPM ( HMA, Mill and Overlay): 0.64 lane- miles/ closure
5)
While the TMP calls for an 8 PM to 6 AM nighttime closure for the initial construction ( CAPM Overlay), the closure window could, and often does, change for future rehabilitation activities.
6)
Check with Traffic Operations or Construction for an appropriate closure window to use Final Surface TypePvmt Design LifeMaint. Service LevelCAPMActivity Service Life ( years) Annual Maint. Cost ($/ lane- mile) 51,100106,10051,100Activity Service Life ( years) Annual Maint. Cost ($/ lane- mile) 106,200106,100100CAPM HMA51Activity DescriptionYear of ActionActivity Description03CAPM HMAYear of ActionCAPM HMABegin Alternative Construction5Year1015HMA5+ 1,2Rehab HMA ( 10 yr) CAPM HMA
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Life Cycle Cost Analysis Procedures Manual November, 2007
with each of the future rehabilitation activities or follow the procedure described in Section 3.3.2. For simplicity in this example, the same closure window will be use in all the future rehab activities as in the initial construction.
7)
Divide the total number of paving lane- miles by the production rate of the preferred construction window to get the “ Work Zone Duration” ( in terms of number of closures required):
( a)
10- year Rehab in Year 5
􀂃
Overlay 20.4/ 0.70 = 29.1 ≈ 30
􀂃
Mill and Overlay 20.4/ 0.37 = 55.1 ≈ 56.
( b)
5- year CAPM in Year 15:
􀂃
Overlay = Same as the above 10- year Rehab in Year 5.
􀂃
Mill and Overlay 20.4/ 0.64 = 31.88 ≈ 32
Inputs to RealCost
1)
CAPM in Year 0: ( to be entered under “ Initial Construction” tab of the “ Alternative 1” panel in RealCost-- see Figure 3- 10)
( a)
Work Zone Length ( miles): 2
( b)
Work Zone Duration ( days): 12
( c)
Work Zone Capacity ( vphpl): 1,510 ( from Table 6)
( d)
Work Zone Speed Limit ( mph): 60
( e)
No of Lanes Open in Each Direction: 1 ( two out of the three lanes closed for single- lane paving)
( f)
Work Zone Hours: Will use 2 periods:
•
First period 0 – 6
•
Second Period 20 – 24
2)
10- year Rehab in Year 5: ( to be entered under “ Rehabilitation 1” tab of the “ Alternative 1” panel in RealCost-- see Figure 3- 10)
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Overlay
Mill and Overlay
Work Zone Length ( miles)
2
2
Work Zone Duration ( days):
30
56
Work Zone Capacity ( vphp from table 6)
1510
1510
Work Zone Speed Limit ( mph)
60
60
No of Lanes Open in Each Direction
1
1
Work Zone Hours
0 – 6
20 - 24
0 – 6
20 - 24
3)
CAPM in Year 15: [ to be entered under “ Initial Construction” tab of “ Alternative 1” panel in RealCost ( Figure 3- 10)]
Overlay ( same as initial)
Mill and Overlay
Work Zone Length ( miles
2
2
Work Zone Duration ( days):
12
32
Work Zone Capacity ( vphp from table 6)
1510
1510
Work Zone Speed Limit ( mph
60
60
No of Lanes Open in Each Direction
1
1
Work Zone Hours
0 – 6
20 - 24
0 – 6
20 - 24
To save the alternative- level inputs file, click the “ Save” button at the bottom of the “ Alternative” panel ( see Figure 3- 10). RealCost will save the alternative- level inputs in the 68
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location and with the name specified by the user. The project alternative- input file will be automatically saved with a *. LCA extension. To load the file when re- entering RealCost, click the “ Open” button located at the bottom of the “ Alternative” panel.
Note:
Be sure to provide the minimum information in all six “ Rehabilitation” tabs to avoid an error message. The minimum inputs are: Activity Service Life, Work Zone Length, Work Zone Capacity, Work Zone Speed Limit, and No. of Lanes Open in Each Direction During Work Zone. Zero can be entered in the remaining input fields.
3.5 Input Warnings and Errors
To see a list of missing or potentially erroneous data, click the “ Show Warnings” button in the “ Switchboard” ( Figure 3- 1) before running the analysis. . Note: “ Warnings” call attention to certain inputs that fall out of expected ranges and do not necessarily indicate input errors. “ Errors” are fatal inputs that will prevent the program from running and providing LCCA results. If “ Warnings” or “ Errors” occur, it is advisable to recheck inputs and project assumptions to ensure the analysis is realistic and accurate.
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Figure 3- 11: Input Warnings
3.6 Simulation and Outputs
The “ Simulation and Outputs” section of the RealCost Switchboard ( Figure 3- 1) includes buttons to view deterministic life- cycle cost results and buttons to run simulations of probabilistic inputs.
•
Deterministic Results: Click this button to have RealCost calculate and display deterministic values for both agency and user costs based upon the deterministic inputs. The “ Deterministic Results” panel ( Figure 3- 12) provides a direct link (“ Go to Worksheet” button) to the “ Deterministic Results Excel Worksheet” that contains all the information needed to investigate the deterministic results.
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Figure 3- 12: Deterministic Results Panel
•
Simulation: Clicking this button will initiate Monte Carlo simulation of probabilistic inputs. At present it is not being used.
•
Probabilistic Results: Clicking this button will display probabilistic results. At present it is not being used.
•
Reports: Click this button to have RealCost produce a twelve- page report ( Figure 3- 13) that shows inputs and results. The last two pages include results of the probabilistic analysis, which will be blank if no probabilistic inputs are entered. 71
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Figure 3- 13: RealCost Report
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3.7 Administrative Functions
The “ Administrative Functions” section of the RealCost Switchboard ( Figure 3- 1) allows the user to save, clear, retrieve data, and close the “ Switchboard” or RealCost.
•
Go to Worksheets: Clicking this button will allow direct access to any input or result worksheet.
•
Clear Input Data: Clicking this button clears the project- level inputs, alternative- level inputs, and results from the program and the worksheets.
•
Save LCCA Workbook As...: Clicking this button allows you to save the entire Excel workbook, including all inputs and results worksheets, under a user- specified name.
•
Exit LCCA: Clicking this button will close RealCost.
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CHAPTER 4 – ANALYZING LCCA RESULTS
Life- cycle cost analysis is a project evaluation tool that compares the economic impacts of different alternatives. The data and procedures in this manual are not designed to provide cost- benefit ( non- economic) or network level analysis. The goal of this LCCA Procedures Manual is to provide consistent analysis by making the same assumptions between equivalent alternatives in order to determine the most cost effective strategy.
The results ( dollar values) from LCCA performed using RealCost and this manual should not be used for project budgeting or estimating. Although life- cycle costs are reported in dollars, the results should be viewed as a relative comparison of cost effectiveness between the alternatives analyzed. The costs generated by RealCost are not an estimate of the actual cost to the Department or the public Life- cycle cost analysis is not a means to predict the future. By using the same methodology ( established by this manual) to analyze alternative pavement strategies over a given analysis period, most differences between assumptions inherent in the analysis and future developments are negated by the comparison between alternatives.
To generate reasonable and consistent results, the alternatives being evaluated through LCCA must provide equivalent benefits, although the costs and scheduled activities between alternatives will typically vary in amount and timing over the analysis period. For example, alternatives that only differ in design life or pavement surface type are considered to have equivalent benefits. Conversely, an alternative that includes widening or increases vehicle capacity is not equivalent to a strategy that only rehabilitates an existing pavement structure. Similarly, a preventative maintenance strategy such as a slurry or chip seal is not equivalent to a pavement rehabilitation overlay that adds design strength to the pavement structure.
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4.1
Status of the LCCA Procedures Manual
This manual includes a variety of tables and data developed for Department users to run the RealCost program, which was developed by the Federal Highway Administration ( FHWA). The data found in this manual is based on the most accurate information available at this time from Department historical data, computer modeling, FHWA, the California Department of Finance, and other sources. Data and modeling improvements will be made from time to time to improve the user- friendliness of LCCA process and the accuracy of the results. In particular, cost data will need to be changed periodically due to market fluctuation, inflation, and policy changes. Future updates of this manual will strive to capture the most accurate information available.
4.2
RealCost
Just as LCCA is a tool for project alternative evaluation, RealCost is a tool for LCCA. As with any tool, RealCost has limits. It is a software program designed to model actual project conditions in order to compare the costs of selected alternatives over a given analysis period ( the life- cycle).
Users should be mindful of the “ garbage in, garbage out” mentality. How well RealCost models a project is determined by the complexity of the conditions and the engineering judgment of the user. To assure the consistency of the analysis and to minimize the amount of time needed to perform an analysis, data tables for costs, schedules, and user cost inputs have been generated using existing Department data and other sources. In some cases ( such as the Future Maintenance and Rehabilitation Schedules in Appendix 4), the data in the tables is the only data to be used for the analysis. In other cases, the data tables are provided as defaults in case more detailed project specific data is not available ( such as in Table 6 or Figure 3- 8).
Although data tables and instructions are intended to cover nearly all the situations that may be encountered with a project, situations will arise that are not covered in the manual. Because
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LCCA involves nearly every aspect of a project, it is advisable to seek out experience within an office, district, or region to take advantage of institutional knowledge within the Department and verify any assumptions made as part of the analysis. As with any engineering analysis or estimate, LCCA calculations should be checked and verified to ensure quality results. At a minimum, the results should be analyzed for input errors, excessive cost differences between alternatives, and given a reality check ( do the inputs and outputs make sense?). The more time and care is invested in developing accurate input data, the better the quality of the results. However, investing more time refining inputs is not always justified since the models in RealCost may not be sensitive enough to certain variables to change the ultimate conclusion of the LCCA. Users can try varying inputs and analyzing the results to see if a finer analysis is warranted.
4.2.1
Project Conditions and RealCost
Despite the numerous inputs in the RealCost program, the geometric and traffic models are relatively simple compared to typical project conditions. For projects with multiple segments, routes, or project types ( new construction and rehabilitation together), the user should break the project down and run RealCost separately for each component to get the most accurate results. For variable closure windows ( number of lanes, day of the week, month, traffic direction), and variable geometrics ( number of lanes available), the user may want to break the project down into multiple segments or scenarios and run RealCost separately for each component to see how the results change. Given the variable sensitivity of the software model to different inputs, an alternative solution is to vary the inputs and analyze the results to determine if more in- depth analysis is necessary. How a project is broken down is subject to the engineering judgment of the user. Potential methods include adjusting the post mile inputs in RealCost or using a percentage of the total cost based on relative project lengths or surface area. For variable Traffic
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Management Plan ( TMP) requirements, a reasonable assumption may be to use the requirements that cover the majority of the project while considering whether they are over- or underestimating user costs.
4.3
Agency and User Costs
LCCA is focused around quantifying two distinct types of costs throughout the project limits over a given analysis period: agency costs and user costs. Agency costs are estimated using engineering quantities and historical costs of previous projects ( initial project estimate), Table 4 ( for existing flexible surfaces) or Table 5 ( for existing rigid surfaces), as well as the M& R Schedules in Appendix 4 of this manual. There are multiple cost inputs aimed at estimating the direct cost to the Department.
User costs are an estimate of the costs associated with delaying the traveling public during initial project construction and subsequent maintenance and rehabilitation activities within the analysis period. They are based on predicted traffic volumes, stage construction, traffic handling, user delay cost rates, and additional vehicle operating costs. User delay cost is calculated by multiplying the additional travel time resulting from roadwork by the assigned user delay cost rate. The additional vehicle operating costs are determined by multiplying the additional vehicle cost ( from speed changes, stops, and idle time) by the assigned dollar value. User costs are related to project activities but are an indirect cost ( not born directly by the Department).
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4.3.1
Limitations of LCCA Results
Agency Costs:
•
In early phases of project development, detailed information is limited, so project estimates for initial construction costs may not be accurate. The most important need at this stage is to be sure that the estimates and assumptions used for each alternative are equivalent and consistent.
•
The Maintenance and Rehabilitation ( M& R) Schedules in Appendix 4 are a model for planning and scheduling pavement activities. They represent a typical scenario for maintaining a particular type of pavement based on previously generated Maintenance decision trees and generally accepted statewide and national practice. The M& R Schedules assume funds will be available to apply the treatments when needed and should not be viewed what has actually been done historically or a guarantee of what will occur in the future.
•
General inflation is not accounted for in LCCA because it is assumed that inflation will be the same for all alternatives. This is considered to be a reasonable approach since the analysis is focused on relative comparison between alternatives. However, future increases in certain material and labor costs or changes in project requirements may cause some products or strategies to inflate at a different rate over time. Since it is not possible to predict how much differential change ( if any) may occur, inflation is not accounted for in the analysis. 78
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User Costs:
•
User costs are sensitive to the assigned user delay cost rate and vehicle operating costs since they are the only cost components of the estimate. To be consistent in comparing alternatives, Caltrans uses rates from the Cal- B/ C ( 2004) model developed by the Office of Transportation Economics in the Division of Transportation Planning.
•
User costs are heavily dependent on assumed staging and traffic handling plans ( number of lanes open, closure hours, productivity, number of closures, and especially maximum queue length), components that are mostly controlled by the contractor and typically vary throughout project construction.
•
The geometric and traffic models in RealCost are relatively simple compared to typical conditions on most projects, which can greatly affect the prediction of user costs. By applying the same assumptions to all alternatives, the analysis should provide a reasonable comparison between alternatives. A more accurate assessment of user costs can be made for some projects by using the CA4PRS software program, which is available on the Division of Research and Innovation ( DRI) website at http:// www. dot. ca. gov/ research/ roadway/ ca4prs/ index. htm.
•
Variations in future growth, user driving habits, and alternate routes available during construction can affect the accuracy of user cost estimates.
4.3.2
Comparing Agency & User Costs
The Department currently considers agency and user costs equivalent, but when analyzing LCCA results it is advisable to compare the individual agency and user costs for each alternative being considered in addition to the total costs. For projects proposed on highway corridors with large traffic volumes, user costs can have significantly greater impact than agency costs. User
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costs for each alternative should be compared to determine if there is a disproportionately high or low impact on users. If an alternative has the lowest agency cost but excessively high user costs, the traffic management assumptions should be re- examined or an alternative that has somewhat higher agency costs but much lower user costs may be preferable.
4.3.3
Choosing an Alternative
Due to the assumptions and variability inherent in the LCCA process, alternatives are considered equivalent if the total LCCA costs for each alternative are within 5% of each other ( 2% if initial costs exceed $ 100 million). Other than the mandatory design standards detailed in Topic 612, “ Pavement Design Life,” of the Highway Design Manual, there is no requirement to choose the alternative with the lowest total life- cycle cost. Some possible reasons to choose another alternative include safety, scope, schedule, constructability, environmental, additional benefits ( such as historical material performance), accommodation of future growth or capacity improvements, or political reasons. Any LCCA project decisions should be justified and documented in the PID, PR, or other appropriate project document ( see PDPM Appendix O- O).
4.4
Projects with Different Pavement Design Lives
When a project has two different pavement design lives within the same project ( such as a widening to last 20 years and an overlay of existing that will last only 5 years), the initial costs will need to be divided into two ( or more) projects representing the costs to do each component with different pavement design lives and analyzed separately using life- cycle cost analysis. The results of the separate life- cycle cost analysis will then need to be combined to produce the overall project result.
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REFERENCES
1.
Federal Highway Administration, “ Life- Cycle Cost Analysis in Pavement Design,” FHWA- SA- 98- 079, Pavement Division Interim Technical Bulletin, September 1998.
2.
Federal Highway Administration, Life- Cycle Cost Analysis, RealCost User Manual, August 2004.
3.
Federal Highway Administration, “ Life- Cycle Cost Analysis Primer,” August 2002.
4.
California Department of Transportation, “ 2004 State of the Pavement,” Division of Maintenance, Office of Roadway Rehabilitation and Roadway Maintenance, July 2005.
5.
California Department of Transportation, “ Highway Design Manual,” Sixth Edition, September 2006.
6.
California Department of Transportation, “ Historical Cost Analysis of Capital Outlay Support for FYs 1998 to 2002,” Division of Project Management, Office of Project Workload and Data Management, May 2005.
7.
Washington State Department of Transportation, “ Pavement Type Selection Protocol,” Environmental and Engineering Program Division, January 2005.
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APPENDIX 1: GLOSSARY AND LIST OF ACRONYMS
A. Glossary
Analysis Period: the period of time during which the initial and any future costs for the project alternatives will be evaluated.
Activity Service Life: the estimated time period that the asset will remain viable for public use ( at or above a minimum level of service).
CApital Preventive Maintenance ( CAPM): CAPM consists of work performed to preserve the existing pavement structure utilizing strategies that preserve or extend pavement service life. See HDM Index 603.2 and the CAPM Guidelines for further information ( DIB 81).
Composite Pavement: pavements comprised of both rigid and flexible layers. Currently, for purposes of the procedures in the HDM, only flexible over rigid composite pavements are considered composite pavements.
Continuously Reinforced Concrete Pavement ( CRCP): one type of rigid pavement with reinforcing steel and no transverse joints except at construction joints or paving stops for more than 30 minutes. CRCP pavements are reinforced in the longitudinal direction, and additional steel is also used in the transverse direction to hold the longitudinal steel. Due to the continuous reinforcement in the longitudinal direction, the pavement develops transverse cracks spaced at close intervals. These cracks develop due to changes in the concrete volume, restrained by the longitudinal reinforcement steel, resulting from moisture and temperature variation. Crack width can affect the rate of corrosion of the reinforcing steel at the crack locations when water or de- icing salts ( if used) penetrate the cracks. In a well- designed CRCP, the longitudinal steel should be able to keep the transverse cracks tightly closed.
Crack, Seat, and Flexible Overlay ( CSFOL): A rehabilitation strategy for rigid pavements. CSFOL practice requires the contractor to crack and seat the rigid pavement slabs, and place a flexible overlay with a pavement reinforcing fabric ( PRF) interlayer.
Flexible Pavement: Pavements engineered to transmit and distribute traffic loads to the underlying layers. The highest quality layer is the surface course ( generally asphalt binder mixes), which may or may not incorporate underlying layers of a base and a subbase. These Life Cycle Cost Analysis Procedures Manual November, 2007
types of pavements are called “ flexible” because the total pavement structure bends or flexes to accommodate deflection bending under traffic loads.
Hot Mix Asphalt ( HMA): formerly known as asphalt concrete ( AC), is a graded asphalt concrete mixture ( aggregate and asphalt binder) containing a small percentage of voids which is used primarily as a surface course to provide the structural strength needed to distribute loads to underlying layers of the pavement structure.
Hot Mix Asphalt with Open Graded Frictional Course ( HMA w/ OGFC): an open graded asphalt concrete wearing course on top of a graded asphalt concrete mixture ( aggregate and asphalt binder) containing a small percentage of voids which is used primarily as a surface course to provide the structural strength needed to distribute loads to underlying layers of the pavement structure.
Hot Mix Asphalt with Rubberized Asphalt Concrete ( HMA w/ RAC): is a rubberized asphalt concrete wearing course on top of a graded asphalt concrete mixture ( aggregate and asphalt binder) containing a small percentage of voids which is used primarily as a surface course to provide the structural strength needed to distribute loads to underlying layers of the pavement structure.
Jointed Plain Concrete Pavement ( JPCP): one type of rigid pavement, also referred to as Portland Cement Concrete Pavement ( PCCP), constructed with longitudinal and transverse joints. JPCPs do not contain steel reinforcement, other than tie bars and dowel bars. JPCPs are doweled in the transverse joints to improve load transfer and prevent faulting of the slabs from occurring. Tie bars are used in the longitudinal joints to hold adjoining slabs together.
Lane Replacement: the removal of individual slabs ( or panels) of concrete pavement with the total length of consecutive slabs is greater than 100 feet.
Maintenance Service Level ( MSL): Caltrans uses a three class system, termed ' Maintenance Service Level' ( MSL), to distinguish the role various highways within the state highway network.
•
MSL 1 – Contains route segments in urban areas functionally classified as Interstate, Other Freeway/ Expressway, or Other Principal Arterial. In rural areas, the MSL 1 designation contains route segments functionally classified as Interstate or Other Principal Arterial
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•
MSL 2 – Contains route segments classified as an Other Freeway/ Expressway, or Other Principal Arterial not in MSL 1, and route segments functionally classified as minor arterials not in MSL 3
•
MSL 3 – Indicates a route or route segment with the lowest maintenance priority. Typically, MSL 3 contains route segments functionally classified as major or minor collectors and local roads, route segments with relatively low traffic volumes. Route segments where route continuity is necessary are also assigned MSL 3 designation.
The MSL can be found in the Pavement Condition Report developed by maintenance at: http:// onramp. dot. ca. gov/ hq/ maint/ roadway_ rehab/ index. htm .
Pavement: The planned