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A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan (2023)

Chapter: Chapter 4 - Incorporating Maintenance into Life-Cycle Planning

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Suggested Citation:"Chapter 4 - Incorporating Maintenance into Life-Cycle Planning." National Academies of Sciences, Engineering, and Medicine. 2023. A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan. Washington, DC: The National Academies Press. doi: 10.17226/27291.
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Suggested Citation:"Chapter 4 - Incorporating Maintenance into Life-Cycle Planning." National Academies of Sciences, Engineering, and Medicine. 2023. A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan. Washington, DC: The National Academies Press. doi: 10.17226/27291.
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Suggested Citation:"Chapter 4 - Incorporating Maintenance into Life-Cycle Planning." National Academies of Sciences, Engineering, and Medicine. 2023. A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan. Washington, DC: The National Academies Press. doi: 10.17226/27291.
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Suggested Citation:"Chapter 4 - Incorporating Maintenance into Life-Cycle Planning." National Academies of Sciences, Engineering, and Medicine. 2023. A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan. Washington, DC: The National Academies Press. doi: 10.17226/27291.
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Suggested Citation:"Chapter 4 - Incorporating Maintenance into Life-Cycle Planning." National Academies of Sciences, Engineering, and Medicine. 2023. A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan. Washington, DC: The National Academies Press. doi: 10.17226/27291.
×
Page 36
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Suggested Citation:"Chapter 4 - Incorporating Maintenance into Life-Cycle Planning." National Academies of Sciences, Engineering, and Medicine. 2023. A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan. Washington, DC: The National Academies Press. doi: 10.17226/27291.
×
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Suggested Citation:"Chapter 4 - Incorporating Maintenance into Life-Cycle Planning." National Academies of Sciences, Engineering, and Medicine. 2023. A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan. Washington, DC: The National Academies Press. doi: 10.17226/27291.
×
Page 38
Page 39
Suggested Citation:"Chapter 4 - Incorporating Maintenance into Life-Cycle Planning." National Academies of Sciences, Engineering, and Medicine. 2023. A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan. Washington, DC: The National Academies Press. doi: 10.17226/27291.
×
Page 39
Page 40
Suggested Citation:"Chapter 4 - Incorporating Maintenance into Life-Cycle Planning." National Academies of Sciences, Engineering, and Medicine. 2023. A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan. Washington, DC: The National Academies Press. doi: 10.17226/27291.
×
Page 40
Page 41
Suggested Citation:"Chapter 4 - Incorporating Maintenance into Life-Cycle Planning." National Academies of Sciences, Engineering, and Medicine. 2023. A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan. Washington, DC: The National Academies Press. doi: 10.17226/27291.
×
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32 Incorporating Maintenance into Life-Cycle Planning What Is Life-Cycle Planning? One method to determine the most cost-effective approach to managing assets is life-cycle planning (LCP). Federal regulations define LCP as “a pro- cess to estimate the cost of managing an asset class, or asset subgroup over its whole life with consideration for minimizing costs while preserving or improving the condition” (23 CFR 515.5). In other words, LCP can be thought of as a whole-life approach to keeping assets in operational condition as cost- effectively as possible. The definition of LCP that is provided includes some terms that would be useful to clarify. • Asset class is a type of asset that has similar characteristics and serves a common function. Bridges, pavements, culverts, and signs are all examples of different asset classes that transportation agencies manage. • Asset subgroup is a set of assets within an asset class that have common characteristics that result in similar life-cycle attributes. For instance, asphalt and concrete pavements are constructed and maintained differently, so the whole-life approach to developing an LCP strategy for them is expected to differ in terms of the type, frequency, and cost of treatments. An LCP analysis allows these differences to be accounted for when agencies have sufficient data for the analysis. FHWA has outlined a five-step process for conducting the analysis, as shown in Figure 4-1. Step 1—Select Asset Classes and Networks: Select which asset classes will be analyzed and what portion of the network will be included (e.g., Interstates, state routes). Step 2—Identify LCP Strategies: Identify the different strategies that will be considered in the analysis. An analysis is a series of treatments that are expected to be applied over an analysis period that could be used to maintain asset conditions. Since different strategies can be used to maintain an asset, it is suggested that multiple strategies be analyzed. For instance, some agencies might analyze a replacement strategy that minimizes the use of planned maintenance. However, this strategy may require a substantial amount of reactive maintenance. Another strategy might evaluate the differences that would occur if the needed replacements could be spaced out by applying some preventive or routine maintenance treatments. To enable an agency to compare results, all strategies are analyzed using the same assumed budget. Ideally, one of the strategies analyzed emerges as the most practical strategy to be used for that asset class or asset subgroup. Step 3—Set LCP Scenario Inputs: Analyze the cost-effective strategy selected in Step 2 to determine what conditions can be achieved at different funding levels and define the analysis C H A P T E R 4 Maintenance activities serve an important role in ensuring that assets remain in safe, operational condition for as long as possible at the lowest practicable cost. The conduct of regular, ongoing maintenance activities is incorpo- rated into pavement and bridge life-cycle designs, manufacturers’ recommended service life estimates, and in operation manuals. Although the importance of maintenance in preserving asset life is recognized, accounting for its contribution in the development of a TAMP is not always a straightforward process.

Incorporating Maintenance into Life-Cycle Planning 33   scenarios. This includes setting targeted conditions, reviewing the expected funding levels that might be available over the 10-year analysis period considered in the TAMP, and determining whether any agency-specified priorities must be addressed. An example of an agency-specified priority might include high-priority bridges on evacuation routes or a culvert replacement program in flood-prone areas. Step 4—Develop LCP Scenarios: Analyze the different scenarios. The results of the analyses can be compared in several different ways, but the resulting conditions (or performance) at the end of the analysis period are the most common. Depending on the results of the analysis, an agency may need to revise one or more of the strategies defined in Step 2, which is why the process illustrated in Figure 4-1 shows a two-directional arrow between these steps. Step 5—Provide Input to Financial Planning: Use the results of the analyses in Step 4 to identify the LCP for the asset that will be incorporated into the TAMP’s financial plan. The results typically become the 10-year planned investment strategy for that particular asset class. Note that for the development of the TAMP, only the level of investment in each asset class and work type is identified over 10 years. The specific projects that are recom- mended as part of the selected strategy are not typically included in a TAMP and are more commonly included in an agency’s Statewide Transportation Improvement Program (STIP) or work plan. The connection between the investment levels in the TAMP and the projects identified in programming documents establishes an important link between an agency’s planning and programming activities. Is Life-Cycle Planning the Same as a Life-Cycle Cost Analysis? Several agencies use a life-cycle cost analysis (LCCA) to compare different design approaches from a cost perspective. In transportation agencies, an LCCA might be used to help an agency determine the type of bridge that might be built or whether a road should be reconstructed with The connection between the investment levels in the TAMP and the projects included in programming documents establishes an important link between an agency’s planning and programming activities. © 2017 Applied Pavement Technology Figure 4-1. Life-cycle planning (adapted from FHWA 2017b).

34 A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan asphalt or concrete. This analysis approach is useful because it considers all the costs that could be incurred over the service life of an asset for each strategy considered. In addition to initial costs associated with the construction of a design alternative, an LCCA considers maintenance and rehabilitation costs that might be incurred at various points over the asset’s life cycle so the design approach with the lowest life-cycle cost can be identified. An LCCA can also consider differences in user costs associated with each design approach, such as differences in travel delay costs due to construction and work zone characteristics that impact users of the facility. An LCCA is similar to an LCP analysis; both use an analysis period that is long enough to evaluate the types of treatments that might be applied over an asset’s life. They also consider that the value of money changes over time using inflation and/or discount rates. Another similarity is considering a range of different treatment types over the life of an asset, including maintenance, preservation, and rehabilitation strategies to extend asset life. Considering different treatments implies that agencies have an idea of how long each treatment will last and when it should be applied. Perhaps the most significant difference between an LCCA and LCP involves the level at which the analyses are conducted. LCP is a network-level analysis. This means that for any selected asset type, the analysis will consider the needs of the entire inventory in the network (e.g., across the state) or a portion of the inventory in a selected subset of the network (e.g., in a single district or on the Interstate). An LCCA is conducted at the project level, which means it typically considers only one potential construction project to determine the preferred design alternative as part of a preliminary engineering project. Because an LCCA considers only one project, the analysis can consider very detailed data specific to the project site such as climate data, traffic volumes and distribution, and soil conditions. In the network-level analysis used for LCP, the same level of detail is not typically available for every asset in the inventory. For that reason, different approaches are used in an LCP analysis than are used when conducting an LCCA analysis. Example: Incorporating Maintenance into Life-Cycle Plans to Improve Resilience Six states including Arizona, Kentucky, New Jersey, Maryland, Massachusetts, and Texas have partnered with FHWA under the “Asset Management and Environmental Risk” pilot program to incorporate extreme weather and climate risk into asset management planning and to evaluate methodologies to incorporate extreme weather and environmental risk into LCP processes (FHWA 2020). Extreme weather events are identified as stressors such as increased precipitation, extreme heat, flooding, storm surge, wildfires, drought resulting from climate change, and rising sea levels. One of the themes that came out of the pilot program was that incorporating event effects in maintenance planning mitigates risks and enhances network resiliency. The major efforts that agencies have undertaken to incorporate climate risk in their TAMPs have been to update their pavement management system (PMS) and bridge management system (BMS) to account for accelerated deterioration of pavement and bridge conditions and failure due to extreme weather events. They have also updated their risk registers to account for climate risks. For example, MDOT SHA focused on incorporating data on pavement and bridge vulnerabilities into its PMS and BMS (MDOT SHA 2019). For pavements, the MDOT SHA has focused on updating the PMS performance models to account for accelerated deterioration due to flooding based on the Hazard Vulnerability Index (HVI) and the percentage of inundation time for each pavement. This captures inundation in modeled deterioration rates and factors it into maintenance and other investment priorities. For bridges, the MDOT SHA has focused on including the HVI score in bridge vulnerability results in the Climate Change Vulnerability Viewer (CCVV) to establish the vulnerability of the bridge approach and to develop a review process for considering risks related to future environmental conditions in project planning. These actions would impact how maintenance is factored into the bridge LCP processes. Similarly, the Kentucky Transportation Cabinet’s (KYTC) efforts have been used to analyze the impact of two major climate threats—extreme heat and extreme precipitation—on pavements and bridges. The consideration of these factors will lead to better planning, maintenance budgeting, and system resilience (KYTC 2019).

Incorporating Maintenance into Life-Cycle Planning 35   Approaches for Considering Maintenance Costs in an LCP Analysis A key to conducting an LCP analysis is the availability of cost and treatment information to represent the strategies for maintaining assets in a serviceable condition. Some agencies have computerized analysis tools that support LCP, such as PMSs and BMSs that use inventory and condition information to predict changes in asset conditions that are best addressed through repair or improvement. These systems typically have analysis capabilities that prioritize suggested improvement by evaluating which combination of projects and treatments provides the greatest benefit for the level of funding expended. While many agencies have these types of systems in place for major assets such as pavements and bridges, fewer agencies have the same level of detail for other assets such as guardrails, ITS assets, and culverts. In many instances, inventories may not be complete, and/or average treatment life may not be known with much certainty. Addi- tionally, although some agencies may have asset inventory and condition information stored in an MMS, the systems are not typically used to determine long-term budget needs. This chapter overcomes these challenges with strategies for considering maintenance costs in an LCP analysis, even if the data can only be estimated. Routine and Operational Maintenance Costs Perhaps the most difficult maintenance costs to incorporate into an LCP analysis are those associated with routine and operational activities since they are commonly applied to restore or sustain functionality without impacting an asset’s life cycle. Examples of the types of activities in this category include graffiti removal, mowing, snow and ice control, and pothole patching. Since these types of activities do not impact an asset’s life cycle, they can be omitted from an LCCA; however, agencies may find it beneficial to include them in the total cost of maintenance activities used in the TAMP’s financial plan. This information can be estimated as an average annual maintenance cost using personnel, equipment, and material costs from an MMS. Preventive Maintenance Costs Preventive maintenance treatments, which may be included in the preservation work type presented in the TAMP, are used to prevent or slow deterioration rather than significantly To analyze these impacts KYTC designed a high-level asset screening tool using National Bridge Inventory (NBI) data to develop flood and scour risk indicators comprising three categories of indicators: the Structural Condition score, the Geomorphic Sensitivity score, and the Criticality Score. The tool allows engineers and maintenance workers to identify risks to bridges and factor them into maintenance planning. Second, the KYTC used the AASHTOWare Pavement ME software to model pavement performance under extreme heat in future climate scenarios. The results showed higher pavement distresses associated with asphalt surface rutting and wheel path fatigue cracking. In addition, the KYTC is focusing on developing maintenance activities that can proactively prepare for extreme precipitation in advance of an event. Kentucky’s 2018 TAMP included several risk statements in its risk register pertaining to extreme precipitation and flooding. Many agencies lack historical data regarding past weather events and maintenance actions taken for response and recovery. Moving forward, agencies can advance the integration of maintenance and TAM by clearly defining maintenance activities in asset management systems. This would allow reporting response and recovery work both by maintenance and capital improvements to help agencies improve investment strategies and budget allocations in preparing for extreme events.

36 A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan improve asset conditions. Since these types of treatments impact an asset’s life cycle, they should be incorporated into an LCP analysis. Assets with Analysis Tools in Place For assets such as pavements and bridges with analysis tools in place (e.g., PMSs and BMSs), preventive maintenance treatments and costs should be incorporated into the decision trees or policies that define the types of treatments considered in the analysis. Two suggestions for considering the cost of preventive maintenance treatments are provided. • Determine whether the preventive maintenance treatments are triggered based on con- ditions, a cycle, or a combination of the two. This will influence the way treatment rules are incorporated into the analysis. For instance, if a preventive maintenance treatment is applied to a pavement approximately 7 to 10 years after an overlay, this cycle will have to be incorporated into a decision-tree rule so it is considered at the right point in the life cycle. If treatments are triggered based on condition, the range of conditions that is suitable for the treatment is defined. For instance, preventive maintenance may be considered on bridges with an NBI rating of 7, 8, or 9. Only bridges within that condition range would be included in estimating preventive maintenance costs each year. • Use pretreatment conditions to determine how the treatment will perform. The perfor- mance of preventive maintenance treatment is influenced by the condition of the asset before the treatment is applied. For instance, a thin overlay will last longer on pavement in good condition than one in fair condition. Ideally, the pretreatment condition can be used to influence the predicted life of the treatment through the development of treatment-specific performance models. If pretreatment information is not available, a single deterioration model will be used regardless of the pretreatment condition. This may result in some inaccuracies in the predicted conditions and the estimated treatment needs. Assets Without Analysis Tools in Place In the absence of an analysis tool, maintenance costs associated with preventive mainte- nance treatments can be estimated based on the expected cycle for their application. For instance, a 10-year cycle implies that 10 percent of the network will be addressed each year. Over the 10 years, 100 percent of the network would be addressed. Not all assets are candidates for preventive maintenance, so it is more realistic to determine the portion of the network that contains suitable candidates for preventive maintenance and estimate what cycle is used for that portion of the network. An LCP estimate of preventive maintenance needs requires at least the following information: • An estimate of the size of the asset inventory. • An estimate of the number (or percentage) of assets in each condition category, such as good, fair, and poor. This can be based on actual data or can be extrapolated from MQA survey results. If no such data are available, the percentages should be estimated based on agency experi- ence and refined with time. • An estimate of the network growth rate for the asset. This typically involves estimating the number of new assets added to the inventory each year (not replaced assets). However, an agency could have a negative growth rate for some assets if a certain asset class is being retired. For instance, high-mast tower lighting might be replaced by other types of lighting assets. • An estimate of the amount of time it typically takes for a new asset to move from one condition to another. Condition states can be defined in any way that is meaningful for the asset class. For instance, it might be appropriate to use good, fair, and poor as the condition states for some assets, but others might be better addressed by compliant or noncompliant. The NDOT case study presented later in this section uses high, medium, and low risk for classifying the

Incorporating Maintenance into Life-Cycle Planning 37   condition of its ITS assets. This establishes a deterioration rate that can be used to estimate the number of assets in a condition state at any point in the analysis. It may also be based on the expected service life, which may be provided by a manufacturer, generated from information in an MMS, or estimated based on agency experience. • A summary of the types of preventive maintenance activities identifies each asset condition state as good, fair, and poor condition. The average cost for these preventive maintenance treatments is estimated based on contract information, bid prices, or information from the MMS. • A determination of how the condition of the asset changes when preventive maintenance is applied. For instance, if an asset in good condition receives a preventive maintenance treat- ment, it likely stays in good condition. For assets in fair condition, a preventive maintenance treatment may move an asset into good condition, or it may keep it in fair condition. The application of preventive maintenance treatment to an asset in poor condition may not have a significant impact on the resulting condition so it may stay in poor condition. • An estimate of the percentage of the network in each condition state that will receive a preven- tive maintenance treatment each year. For instance, an agency may target 10 percent of the assets in fair condition and 2 percent of the assets in good condition for preventive main- tenance each year. These numbers have a significant influence on the estimated budget that will be needed for preventive maintenance, so an agency may want to test different values to determine their impact on the funding need. The resulting conditions at the end of the analysis period can also be useful in setting achievable performance targets for the asset class. This information can then be incorporated into a spreadsheet or web-based tool that models the changes in asset conditions and the amount of preventive maintenance work that will be conducted over the 10 years covered in the TAMP or other agency planning documents. Using the average cost per treatment category, an annual cost can be estimated. Note that this type of analysis does not indicate where the work should be done. Instead, it provides an estimate of the level of funding needed to address preventive maintenance needs at a network level. Alternate strategies can be evaluated by changing the amount of time it takes for an asset to change from one condition state to another, the percentage of assets in each condition category that will receive a preventive maintenance treatment, or the resulting impact of preventive maintenance treatments. This type of analysis was used by the NDOT for its ITS assets as explained in the example. Example: NDOT’s 2019 TAMP and Inclusion of ITS Assets NDOT’s 2019 TAMP includes a description of the LCP approach used for ITS assets (such as closed-circuit TV cameras, flow detectors, and ramp meters) (NDOT 2019). These assets were included in the TAMP because the number of ITS assets on the system was growing, and the agency wanted to estimate future maintenance needs to ensure they remained in operational condition. Although an extensive inventory of the ITS assets had not been conducted, NDOT had sufficient information to estimate the number of assets in the inventory and the distribution of those assets into condition categories using the recommended service life provided by each device’s manufacturer. NDOT then created deterioration models for each ITS asset based on the average amount of time the asset takes to deteriorate from one condition state to another. The matrices were used to model the deterioration of these assets based on expert opinion provided by NDOT. The matrices described the time required for the asset to deteriorate from one condition state to another. The condition states were modeled based on the degree to which the recommended service life had been exceeded. An asset that was still within 80 percent of the recommended service life was considered in good condition. Other condition categories representing Low, Medium, and High Risk were defined as follows: • Low risk: Device age is between 80 and 100 percent of the manufacturer’s recommended service life. • Medium risk: Device age is between 100 and 125 percent of the manufacturer’s recommended service life. • High risk: Device age is greater than 125 percent of the manufacturer’s recommended service life.

38 A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan Repair Costs For purposes of this project, repairs are considered activities that improve asset conditions and functions without improving structural condition or capacity. For example, tightening the bolts on an overhead sign structure or slab jacking a sidewalk may be considered repair activities. Assets with Analysis Tools in Place For assets like pavement and bridges, repairs are generally included in capital improvements that are normally considered in a PMS or BMS. There- fore, the costs of these repairs are usually already incorporated in the LCP analysis as minor rehabilitation or preservation treatments. Assets Without Analysis Tools in Place Repairs are common for assets other than pavements and bridges and their costs can be estimated using the same steps outlined for preventive mainte- nance activities. Unit or Component Replacement Costs Unit or component replacements are used to restore the functionality of an asset (or component) at the end of its service life. Many assets rely on replace- ments to achieve expected levels of retroreflectivity on sign panels, to refresh striping, or to address outdated ITS equipment. Assets with Analysis Tools in Place Bridge and pavement replacements are considered at the end of an asset’s service life. This treatment type is normally considered in a PMS or BMS as a capital improvement. Therefore, the costs associated with replacements are typically already incorporated into their LCP analysis. The NYSDOT recognized that the number of bridges requiring replace- ment was increasing faster than replacements could be scheduled. To address this issue, the agency initiated a structural repair program that changed the LCP strategy by extending bridge service lives and slowing the rate at which bridge replacements were needed. This strategy is described in an example. Assets Without Analysis Tools in Place Unit and component replacements are also common with assets that have reached the end of their service life. The estimated cost of needed replace- ments can be found using the Manufacturer’s Estimated Service Life or as part To support the analysis, NDOT defined the maintenance activities that need to be performed on ITS assets, including inspections, minor repair, major repair, and replacement. NDOT also created a matrix that shows the impact of each activity on asset condition. For instance, a major repair applied to an ITS asset in the medium-risk category would be moved to the low-risk category after the repair was applied. The LCP analysis evaluated two different strategies—one reflected the preservation approach adopted by NDOT, and the other was a “worst-first” strategy in which the devices received no minor repairs or maintenance and would be replaced when they failed. The analysis showed that the long-term cost of employing NDOT’s maintenance strategy was much lower than the worst-first approach and provided an estimate of annual maintenance costs for maintaining these assets. Managing Obsolescence Unit replacement is common for electronic components of systems such as traffic signals or ITS instal- lations because many of these units are not repairable. In these cases, when units reach the end of their service lives they must be replaced. As technology changes, manufacturers stop supporting older technology in support of newer technology. This may mean that the unit being replaced cannot be replaced in-kind. If a compatible replacement unit cannot be obtained, it may require replacement of multiple elements to restore functionality. In some cases, new technology is made compatible with older standards. An example of this is traffic LED signal lanterns that can be used in place of incandescent units. In other cases, such as signal controller boards, newer technology may not be compatible with older installations. Maintenance and asset managers must work together to identify technology that is at risk of becoming obsolete to identify strategies that keep existing assets in service or replace assets with the newer technology.

Incorporating Maintenance into Life-Cycle Planning 39   of the analysis described for preventive maintenance activities. In this instance, the treatment to be considered would be replacement, and it is likely applied to assets in poor condition. Once a replacement is complete, the asset’s condition changes to “good,” where it becomes a candidate for other types of treatments. Organizational Strengthening Costs Organizational strengthening activities do not address asset conditions, so they are not typi- cally included in an LCP analysis. However, as with costs associated with operations and routine maintenance, they are part of the total maintenance budget and may be included in the TAMP financial plan. Understanding the Cost to Maintain New Assets The addition of new assets to an inventory brings with it a future demand on maintenance to keep them in operational condition and working safely. This added burden on maintenance is often not considered in developing maintenance budgets or future needs. Therefore, in an agency that is growing its asset inventory, maintenance needs can be significantly underestimated if they are not incorporated into an LCP analysis. Growth Rate Approach One way to address this is to incorporate a growth rate into the analysis, as suggested in the third bullet, previously under Preventive Maintenance Costs, Assets Without Analysis Tools in Place. The inclusion of the growth rate enables an agency to incorporate new assets into the analysis so future maintenance needs can be estimated. It does this by inserting an estimated number of new assets into the inventory so they are considered in the calculation of the amount of work needed in each year of the analysis. This growth rate, which may vary by district due to variations in traffic, could be based on a review of several years’ worth of contracts to see how Example: NYSDOT Use of Structural Repairs to Defer the Need for Bridge Replacements Over the years, NYSDOT implemented innovative bridge design elements, such as continuous-span (or jointless) bridges, to reduce the need for preventive maintenance. As a result of a constant rate of replacement (approximately 1 percent per year by bridge deck area) and newer bridges requiring less preventive maintenance work, by the early 2000s, the need for preventive maintenance bridge treatments was steady or decreasing on an annual basis. Simultaneously, due to the overall aging of the state's bridges, the need for more substantial repairs was increasing. To address the shifting maintenance needs of its aging bridge inventory, NYSDOT revised the bridge maintenance program to focus on structural repairs that extended bridge service life. These treatments addressed localized deterioration to keep the bridges functional and extend the design life by 20 years. NYSDOT used LCP to review the current condition of its assets and establish the needed work over the TAMP analysis period. The service-life-extension approach suggested allocating resources so that the state's newer bridges receive preventive maintenance treatments. The life-extension approach has led to an increase in the level of resources dedicated to performing maintenance repairs to address elements rated in Poor condition. These repairs may not have impacted the overall bridge condition rating, but they reduced risks and extended service life. Since adopting the service-life-extension approach, NYSDOT started retraining and equipping its staff to perform repairs under the deck to superstructure and substructure elements. This included training in construction skills for heavy work activities like forming and pouring, welding, lead paint abatement, and metal preparation. NYSDOT also invested in equipment to provide access under the bridge deck, such as lifts and under bridge inspection units (UBIU).

40 A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan many new assets are being added each year. Individual growth rates for each district could be rolled up to a statewide average if the LCP analysis is being done to reflect agency-wide needs. Assumptions about how the new assets deteriorate or the schedule for their replacement are based on the assumptions used for existing assets, as input into the spreadsheet analysis or man- agement system. Although adding expected new assets to the inventory may complicate the analysis, it may be worth the trouble if an agency is quickly adding new assets. This is especially applicable to agencies that are adding ITS assets or other forms of technology to support performance goals related to safety or mobility. An analysis conducted by MnDOT as part of its initial TAMP development analyzed the life-cycle cost associated with adding 1 mile of pavement to its existing inventory. The analysis found that with a typical life-cycle strategy for maintaining the pavement, the total maintenance and rehabilitation cost for that 1 mile was 142 percent of the initial construction cost, meaning that the cost of maintenance and rehabilitation for that mile of pavement was nearly 1½ times the cost of its initial construction (MnDOT 2014). Estimates for maintaining other assets (including inspection costs) as a percentage of the initial cost from the same study are listed below: • Bridges: 142 percent. • Large culverts: 139 percent. • Highway culverts: 443 percent. • Deep stormwater tunnels: 252 percent. • Overhead sign structures: 129 percent. • High-mast light tower structures: 96 percent. These costs are expected to vary by agency based on the types of maintenance applied, the cost of maintenance activities, the selected inflation/discount rate, and the life-cycle strategy used by the agency. However, they indicate that the future maintenance and rehabilitation costs related to new construction or the addition of new assets can be substantial. This growth rate can be annualized using information from the MMS. With data on historical investment levels to maintain an asset class, agencies can estimate the annual increase in funding needed to maintain the assets added to the inventory. If the tool used to perform the life-cycle analysis includes maintenance costs, this analysis of past maintenance investments can be used to refine the growth rate approach. If the asset management system does not include mainte- nance activities, the results of this analysis may be added to the growth rate estimate. Understanding the Cost of Delayed Maintenance NCHRP Research Report 859: Consequences of Delayed Maintenance of Highway Assets provides guidelines on quantifying the consequences of delayed maintenance on highway infrastructure (Chang et al. 2017). The effect of delayed maintenance can be quantified through a multistep process. Maintenance could include several different work types—such as operations and routine maintenance, preventive maintenance and repair, and unit or major component replacement— and could be triggered based on condition, interval, risk, or reactive. For pavements, the performance targets relating to the pavement condition (e.g., surface dis- tresses, roughness, rutting, and faulting) can be used to set up objectives, and treatment triggers can help identify when maintenance is due. Based on the current condition, forecasted future condition, and investment needs analysis, delayed maintenance scenarios could be developed for 5, 10, 15, or 20 years and compared to the baseline (“all needs”) scenario to estimate the costs of the delay. The analysis could be performed using the agency’s PMS or using tools developed by

Incorporating Maintenance into Life-Cycle Planning 41   FHWA that are described in Appendix C of NCHRP Report 859. The scenario analysis quantifies the effect of delayed maintenance on future pavement network condition, future budget needs, backlog, and asset valuation. A similar approach could be implemented for other assets including bridges, culverts, and guardrails. The types of maintenance activities should be defined clearly for each asset. For bridges, the performance objectives could be the percentage of bridges in good, fair, poor, or severe condition based on the NBI condition ratings or the percentage of bridges classified as structurally deficient. Similarly, for culverts, the objective could be the percentage of culverts in good, fair, and poor condition. Alternatively, culvert age and remaining service life could be used as performance measures. For guardrails the percentage of damage to the guardrail system or the percentage of the guardrail system rated below standard could be used to assign a LOS grade of A through F. Deterioration modeling can be based on transition probability matrices.

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Since 2018, State departments of transportation (DOTs) have been required to develop risk-based transportation asset management plans (TAMPs) and to update processes for developing these plans every four years. To date, several DOTs have described challenges in showing clear connections between maintenance investments and asset condition.

NCHRP Research Report 1076: A Guide to Incorporating Maintenance Costs into a Transportation Asset Management Plan, from TRB's National Cooperative Highway Research Program, leads practitioners through a six-part framework designed to tackle the biggest challenges agencies face in projecting future maintenance costs in TAMP activities. Supplemental to the report is a pocket guide.

Supplemental to the report are NCHRP Web-Only Document 372: Incorporating Maintenance Costs into a Transportation Asset Management Plan, an Executive Summary, an Implementation Memorandum, an Overview Presentation, and a Publication Announcement.

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