Consequences of Delayed Maintenance of Highway Assets (2017) / Chapter Skim
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19 Delayed maintenance affects an asset's future condition and its ability to meet the performance objectives established by the highway agency. The procedure to quantify the consequences of delayed maintenance of highway assets involves comparing changes in the asset condition and other performance measures under delayed maintenance scenarios.
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20 Consequences of Delayed Maintenance of Highway Assets affect performance over time (e.g., material type, traffic, environment)
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 21 • Deterioration of an asset's condition over time, • Decreases in an asset's remaining life, • Increases in an agency's future costs to recover the desired level of service (LOS) , • Increases in backlog costs over time, and • Decreases in the asset group's value over time.
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22 Consequences of Delayed Maintenance of Highway Assets – Dowel bar retrofit, – Full-depth concrete patching, – Joint resealing, – Partial-depth concrete patching, – Thin asphalt overlay, and – Ultra-thin bonded wearing course. 3.2.1.2 Performance Objectives Pavement performance objectives are targets, defined by performance measures and commonly expressed in terms of agency-specific treatment trigger values.
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 23 3.2.1.3.2 Maintenance Activities Based on Condition Trigger Values. Table 4 shows a sample set of default trigger values for IRI, cracking, rutting, and faulting used in the Pavement Health Track Tool (PHT)
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24 Consequences of Delayed Maintenance of Highway Assets value. Alternatively, probabilistic models can be used to generate a range of values that express the likelihood of occurrence of a certain condition state.
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 25 Delayed pavement maintenance scenarios are compared to the baseline scenario to quantify the consequences of the delay. The analysis period can be 5 years, 10 years, 20 years, or longer, depending on the agency's planning period.
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26 Consequences of Delayed Maintenance of Highway Assets • Backlog costs, and • Asset value of the pavement network. The specific results and comments reported in the example detailed in Appendix C are summarized as follows: • Scenario 1.a, "All needs," requires a total agency expenditure of $325 million to implement the agency-desired maintenance program and preserve the highway network over the 20-year analysis period.
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 27 result of these activities, but deterioration is expected to be delayed" (FHWA 2011)
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28 Consequences of Delayed Maintenance of Highway Assets • Percentage of bridges classified SD; • Percentage of bridges classified SD or functionally obsolete (FO) ; • Average Sufficiency Rating (SR)
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 29 reasonableness. If the agency does not use a BMS to support the analysis, additional work will be required to define a set of transition probability matrices, or to develop an equivalent set of models to predict bridge performance.
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30 Consequences of Delayed Maintenance of Highway Assets Data Performance Models Maintenance Scenarios (Length of analysis = 20 years *
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 31 a 20-year deferral scenario totals about $12.5 billion. Dividing these amounts by the relative cost reductions ($659 million for the 10-year deferral and $1,483 million for the 20-year deferral)
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32 Consequences of Delayed Maintenance of Highway Assets along with traffic disruption and time delays from road closures. Public safety and risk reduction are priorities in culvert management, followed by preservation activities to reduce life-cycle costs (Markow 2007)
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 33 Performance Measure Description Source NBI Culvert Rating 0–9 rating similar to the deck, superstructure and substructure ratings for bridges FHWA (1995b) FHWA Federal Lands Highway Condition Rating Good, fair, poor, critical, unknown Hunt et al.
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34 Consequences of Delayed Maintenance of Highway Assets 3.4.2 Culvert Maintenance and Budget Needs 3.4.2.1 Assess the Culvert System Condition To evaluate the culvert condition, the following types of inspections are suggested (Ohio DOT 2014) : • Inventory inspections that are conducted upon construction, • Routine inspections that are performed regularly to identify any physical or functional changes, • Damage inspections that are performed on culverts with known defects after major floods and storms to identify any damage that would require load restrictions or road closures, • Interim inspections that are conducted upon expert decision to perform an inspection on culverts that have known defects, and • Storm sewer inspections that can be either inventory or routine checks on storm sewers.
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 35 of culvert life from NCHRP Report 713: Estimating Life Expectancies of Highway Assets (Ford et al.
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36 Consequences of Delayed Maintenance of Highway Assets defaults in the model are to perform maintenance work on a culvert when it has a rating of 4 or 5, and to replace a culvert when it has a rating of 3 or less. When no maintenance work is performed on a culvert, its deterioration is predicted probabilistically using the values specified in Table 13.
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 37 3.4.3.2 Delayed Maintenance Scenario Analysis Appendix E provides a detailed example that includes analysis of the scenarios listed in Table 14. Table 15 summarizes the results of the scenario analysis, including the total costs over a 20-year analysis period and total costs discounted at a rate of 7%.
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Scenario Description Total Agency Cost 1 Discount Agency Cost Backlog Cost 1 Percentage of Culverts in Poor Condition Average Culvert Condition Rating End of Year 20 Critical Year End of Year 20 Critical Year 1 All needs $45.2 million $27.3 million $0 0.0 3.7 (Year 1)
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 39 3.5.1 Guardrail Preservation Policy 3.5.1.1 Types of Maintenance Activities Guardrails' strong association with public safety means repairs are normally performed immediately after an incident report or notification is received. Depending on the damage and the available resources, various maintenance activities can be applied to the guardrail system.
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40 Consequences of Delayed Maintenance of Highway Assets The calculated percentage of deficient guardrail length to total guardrail length determines the grade. If 0% to 10.02% of guardrail length in the system is deficient, the system falls into the "A" grade range (with 89.98% to 100% percent of guardrail length in acceptable condition)
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 41 3.5.2.2 Performance Models for Forecasting Guardrail Condition Guardrail assets are maintained based on condition. For example, the Utah DOT uses regression curves based on performance versus the annual cost to maintain the asset.
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42 Consequences of Delayed Maintenance of Highway Assets Data Performance Models Maintenance Scenarios (Length of analysis: 10 years) Results Guardrail System Database with Inventory and Condition Assessment Deterioration models based on transition condition probability matrices to model the increase/decrease in deficient guardrails 1.
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 43 • Scenario 4.a, "Budget driven with limited funds" using 80% of the baseline budget, results in $11.65 million of agency costs for total work performed and $30.84 million in backlogged costs, with 38% of the system rated Grade F at the end of Year 10. • Scenario 4.b, "Budget driven with limited funds" using 55% of the baseline budget, results in $7.96 million of agency costs for total work performed and $55.13 million in backlogged costs, with 62% of the system rated Grade F at the end of Year 10.
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44 Consequences of Delayed Maintenance of Highway Assets dirt depreciation (LDD) factor, which accounts for characteristics such as "luminaire type, mounting height, environment of the luminaire location (i.e., urban or rural setting)
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 45 3.6.2 Lighting Maintenance and Budget Needs 3.6.2.1 Assess the Lighting System Service Life Lighting service life is usually determined based on agency experience, professional judgment, and manufacturer's data; however, assets often are "repaired or replaced as soon as they fail without regard to service life" (Markow 2007)
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46 Consequences of Delayed Maintenance of Highway Assets 7. Energy costs are tabulated, accounting for the savings in energy costs from not operating failed lights and the reduced energy costs of operating LED lamps relative to HPS lamps.
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 47 3.6.3.2 Delayed Maintenance Scenario Analysis Appendix G presents a detailed example that includes analysis of the various maintenance scenarios. Table 22 summarizes the results of all the scenarios with the 10-year agency total cost and percentage of the lighting system in service.
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48 Consequences of Delayed Maintenance of Highway Assets • Scenario 2 simulates a 10-year deferral period, which reduces the agency's costs by approximately $8.9 million and energy costs by approximately $3.2 million; however, deferring maintenance increases overall life-cycle costs by approximately $200.3 million because of increased crash costs. Also, by the tenth year of deferral, the lighting system value decreases by $13.8 million, as almost half of the lighting system is not in service.
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 49 • "Not required to be retroreflective": Pavement markings that occur where ambient illumination assures adequate visibility or where the markings are needed only during the day (e.g., at a park where access is restricted to daytime hours) "do not require minimum levels of retroreflectivity." All other pavement markings must meet some level of retroreflectivity.
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50 Consequences of Delayed Maintenance of Highway Assets Pavement markings below 150 mcd/m2/lux (Category F) are scheduled for repainting to restore retroreflectivity to 375 mcd/m2/lux (well above the lower retroreflectivity limit for Category A)
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 51 2. The deterioration rate is based on minimum retroreflectivity at the beginning of the service life, retroreflectivity at the end of functional service life (Bahar et al.
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52 Consequences of Delayed Maintenance of Highway Assets 3.7.3 Consequences of Delayed Maintenance of Pavement Markings 3.7.3.1 Formulate Delayed Maintenance Scenarios Table 25 summarizes the key elements needed to analyze the set of scenarios recommended in this study for pavement markings. 3.7.3.2 Delayed Maintenance Scenario Analysis Appendix H provides an example, together with a detailed analysis of each scenario.
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 53 as approximately 38% of the pavement system is below required retroreflectivity levels at the end of Year 5. • Scenario 4.a, "Budget driven with limited funds" using 80% of the baseline budget, reduces the agency's costs by approximately $5.3 million, but unfunded backlog increases by approximately $3.6 million due to delayed maintenance, and 19% of the pavement marking system is below required retroreflectivity levels at the end of Year 5.
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54 Consequences of Delayed Maintenance of Highway Assets 3.8.1 Highway Sign Preservation Policy Sign retroreflectivity preservation policies must correspond to the requirements of the MUTCD (FHWA 2009)
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 55 within a group or sector (Table 27)
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56 Consequences of Delayed Maintenance of Highway Assets Each condition category has an associated treatment. Sign groups in Category A receive "Do nothing" treatment.
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Procedures to Quantify Consequences of Delayed Maintenance of Highway Assets 57 3.8.3.3 Report the Consequences of Delayed Maintenance At the beginning of the analysis, 42% of the highway system sign groups are in Category A, and 15% percent are in Category F Delaying maintenance activities results in increased needs over time and increased numbers of signs in Category F
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58 Consequences of Delayed Maintenance of Highway Assets department or division, responsibility for managing each asset group may fall under different agency offices (e.g., bridges may be managed by a Bridge Office, pavements by a Materials or Design Office)
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