CHAPTER 2

Literature Review

Introduction and Overview of Transportation Asset Management Requirements

Transportation infrastructure, comprising roads, bridges, and a variety of other assets, forms the backbone of transportation systems, facilitating mobility and economic development. Among these systems, ancillary assets, including signage, lighting, and drainage systems, are indispensable components that complement core infrastructure elements, ensuring safety, functionality, and user satisfaction. This literature review delves into transportation asset management in general and then into the management of ancillary assets in transportation infrastructure. Prior to these topics, the following definitions from the FHWA’s Handbook for Including Ancillary Assets Transportation Asset Management Programs are fundamental to understanding this discussion (Allen et al. 2019):

An Asset is a physical roadway infrastructure item that has value. Assets are sometimes referred to as roadway “furniture” or “features.” An asset may be a single item, such as a sign, or a linear item, such as a road or guardrail section. An asset may also be a spatial item such as a rest area or mowable acreage.

Asset Management is a strategic and systematic process of operating, maintaining, and improving physical assets, with a focus on both engineering and economic analysis based on quality information, to identify a structured sequence of maintenance, preservation, repair, rehabilitation, and replacement actions that will achieve and sustain a desired state of good repair over the life cycle of the assets at minimum practicable cost.

These definitions are similar to those in the federal code, specifically 23 CFR Part 515.

Asset means all physical highway infrastructure located within the right-of-way corridor of a highway. The term asset includes all components necessary for the operation of a highway, including pavements, highway bridges, tunnels, signs, ancillary structures, and other physical components. (https://www.ecfr.gov/current/title-23/chapter-I/subchapter-F/part-515)

Asset management means a strategic and systematic process of operating, maintaining, and improving physical assets, with a focus on both engineering and economic analysis based upon quality information, to identify a structured sequence of maintenance, preservation, repair, rehabilitation, and replacement actions that will achieve and sustain a desired state of good repair over the life cycle of the assets at minimum practicable cost. (https://www.ecfr.gov/current/title-23/chapter-I/subchapter-F/part-515)

Additional definitions may be reviewed in the glossary of this report.

Transportation Asset Management Legislation and Policy

The evolution of transportation asset management can be traced back to the late 20th century, with the emergence of systematic approaches to infrastructure management. Early frameworks focused primarily on pavement and bridge assets, with limited attention given to ancillary assets.

However, as DOTs recognized the importance of these assets in supporting overall network performance, efforts to develop comprehensive asset management frameworks expanded to include ancillary assets. Milestones in this development include the establishment of the FHWA’s National Highway System and the adoption of performance-based management practices (FHWA 2019a).

Beginning with the 2012 Moving Ahead for Progress in the 21st Century (MAP-21) Act, asset management became a performance- and outcome-driven program by requirement. The objective of this performance- and outcome-based program was for DOTs to invest resources in projects that make progress toward the achievement of national goals (FHWA 2012a). Performance-based planning and programming (PBPP) for transportation assets has been at the core of the two additional federal transportation reauthorization bills since the MAP-21 Act. These include the 2015 Fixing America’s Surface Transportation (FAST) Act and the 2021 BIL (Iowa DOT 2023). However, MAP-21 was the legislation that set the stage for transportation asset management as practiced by DOTs today. MAP-21 established seven national performance goals for federal highway programs, as seen in Table 2.1 (FHWA 2012a). All of these goals have a connection to ancillary assets and the management of their performance.

MAP-21 also mandated several key points regarding transportation asset management. Specifically, it emphasized the importance of asset management as a strategic approach for optimizing the performance and longevity of transportation infrastructure. MAP-21 mandated the establishment of performance management frameworks for various aspects of transportation but included this as a requirement for pavement and bridge conditions. These performance measures serve as key indicators for assessing the effectiveness of asset management strategies and guiding investment decisions. MAP-21 encouraged the adoption of a risk-based approach to asset management, wherein DOTs assess the condition, performance, and risks associated with different asset types to prioritize maintenance and investment strategies. This approach aims to allocate resources efficiently based on the criticality and vulnerability of assets. Additionally, MAP-21 promoted using life-cycle cost analysis in asset management decision-making. By considering the full cost of owning, operating, and maintaining assets over their life cycle, DOTs can make

Table 2.1. Performance management goals under MAP-21.

Source: FHWA (2012a).

more informed investment decisions that optimize long-term performance and minimize life-cycle costs.

Additionally, MAP-21 emphasized the importance of data collection, analysis, and reporting in asset management. DOTs must establish systems for collecting and managing asset inventory data, condition assessments, and performance metrics to support informed decision-making and accountability. MAP-21 required each DOT to develop and implement a state TAMP that outlines strategies for managing and preserving transportation assets effectively. These plans are intended to be comprehensive and data-driven, incorporating various asset classes beyond pavements and bridges. Compliance with MAP-21 is tied to certain federal funding programs. DOTs must demonstrate progress in developing and implementing TAMPs and meeting performance targets to qualify for federal funding allocations. Overall, MAP-21 provided a legislative framework that underscored the significance of asset management in enhancing the efficiency, safety, and resilience of transportation infrastructure. It aimed to promote a systematic and proactive approach to managing assets, thereby supporting the long-term sustainability of transportation networks across the United States (FHWA 2012b).

Beyond MAP-21, the FAST Act made very few changes to the established asset management program requirements. These changes included timelines for DOTs to achieve performance targets and other minor additions (FHWA 2016). This approach remained until revisions occurred via the Infrastructure Investment and Jobs Act (IIJA). While the requirements regarding asset management remained largely the same, IIJA did add a requirement for consideration of extreme weather and resilience in life-cycle cost and risk management analyses (FHWA 2021).

At its core, transportation asset management (TAM) is a strategic approach to managing transportation infrastructure assets. It involves making cost-effective decisions for maintaining, operating, and improving transportation infrastructure. Legislation and policy play crucial roles in shaping the framework within which TAM operates. This framework is visualized in Figure 2.1, illustrating the complexity of asset management decisions.

While complicated, TAM, founded in performance and planning, is a valuable endeavor and is promoted by FHWA. A 2019 FHWA white paper highlights the interconnection of performance measures, performance-based management, and their application in asset management approaches (FHWA 2019b). The MAP-21 approach promotes the transparency of decision-making and improves accountability of public spending by linking investments to outcomes. Other agencies, such as the Chicago Metropolitan Agency for Planning, support this concept, as visualized by the graphic in Figure 2.2.

The support for asset management by FHWA is witnessed in a review of its asset management website (https://www.fhwa.dot.gov/asset/), providing access to publications, guidance, resources, policy, and requirements. Beyond the resources cited in the chapter, FHWA’s website provides a vast library of reference materials for DOTs developing or expanding asset management programs.

Overview of Transportation Asset Management Plans

TAM is underpinned by various theoretical frameworks from engineering, economics, operations research, and management science. One of the fundamental principles of TAM is life-cycle cost analysis, which considers the total cost of ownership over the entire lifespan of an asset, including acquisition, operation, maintenance, and disposal (Zimmerman et al. 2019). The application of risk management principles, such as probability theory and decision analysis, helps DOTs prioritize investments and mitigate potential failures. Additionally, TAM draws upon concepts from performance management, sustainability, and resilience to optimize transportation networks’ overall performance and resilience. However, achieving this requires a plan.

TAMPs provide a centralized point for DOTs to communicate their assets and management strategies, long-term expenditures, and business management processes. With time, these plans can become an important tool for a DOT to demonstrate sustainable asset management, efficient use of resources, and budgetary justification to the public. TAMPs are an essential management tool for bringing together business processes and stakeholders, internal and external, with transparent information regarding asset condition, performance, and improvements. The TAMP includes analysis, planning options, programs, delivery mechanisms, and reporting mechanisms to ensure strategic objectives are achieved (FHWA 2024).

DOTs are “required to develop a risk-based asset management plan for the National Highway System (NHS) to improve or preserve the condition of the assets and the performance of the system.” (23 U.S.C. 119(e)(1), MAP-21 § 1106). States must address pavements and bridges within their TAMP, and they are encouraged to include additional infrastructure assets within the right-of-way in their asset management plan. DOTs may also include roads other than those on the NHS. At a minimum, the TAMP must include (FHWA 2024):

A summary listing of the pavement and bridge assets on the NHS within the state, including a description of the condition of those assets;

Asset management objectives and measures;

Performance gap identification,

Life-cycle cost and risk management analysis,

A financial plan, and

Investment strategies.

TAMP development involves a vast array of considerations for DOTs. One consideration is which, if any, ancillary assets to include in the TAMP, considering the resources (e.g., staff, data) required to manage those ancillary assets. Some DOTs decide to initiate their TAMP with only the required assets of pavements and bridges on their NHS system but later grow those plans to include ancillary assets. Approaches to include these ancillary assets may involve classifying them in varying ways.

Classification Frameworks of Ancillary Assets and Maturity

Ancillary assets encompass many infrastructure components beyond the primary road and bridge structures. Definitions and classifications of ancillary assets vary across jurisdictions and DOTs. While some categorize ancillary assets based on their functional roles (e.g., safety, aesthetic, operational), others prioritize their physical characteristics or significance in supporting transportation networks (Allen et al. 2019). California DOT (Caltrans) presents the assets in its TAMP graphically, as seen in Figure 2.3.

Establishing clear definitions and classification frameworks aids in prioritizing maintenance activities, allocating resources effectively, and developing targeted management strategies tailored to the specific needs of each asset category. First, it is important to define an ancillary asset: “Ancillary Asset: All physical infrastructure assets other than pavements and bridges, as defined by 23 U.S.C. 119, that a transportation agency wishes to or does manage” (Allen et al. 2019).

One classification of ancillary assets can be found in the Handbook for Including Ancillary Assets in Transportation Asset Management Programs, as seen in Table 2.2 (Allen et al., 2019). These broad-ranging functional areas and asset classes may not align with an individual DOT’s

Table 2.2. Typical asset classes.

Source: Allen et al. (2019).

classifications, as some DOTs avoid using the term “roadside hazard” because it is not a liability-neutral term. This concept is discussed in NCHRP Legal Digest 83: Guidelines for Drafting Liability Neutral Transportation Engineering Documents and Communication Strategies (Parker 2020). There can be other reasons for variations as well.

Other frameworks for classifying ancillary assets use forms of hierarchy or prioritization. Rose et al. (2014) prepared the classification as seen in Figure 2.4.

Another form of classification and prioritization may occur by arranging the management of assets into prioritization tiers. The approach used by Minnesota DOT (MnDOT) was captured by Zimmerman and Allen (2023) and in NCHRP Synthesis 628 by Nassereddine et al. (2024), which also highlights the tiers used by Utah DOT. The tiers developed by MnDOT are as follows (Zimmerman and Allen 2023):

• Tier 1: Bridges, pavements, rest areas, radio towers, intelligent transportation systems (ITS), and signal systems.

• Tier 2: Earth retaining structures (ERS), culverts, high mast tower lights, and frontage roads.
• Tier 3: Deep stormwater tunnels, weigh stations, pavement markings, and roadway lighting.
• Tier 4: Concrete noise walls, snow fences, trees, and storage sheds.

Maintenance of ancillary assets assists in their longevity, functionality, and optimal performance. Feng et al. suggest that traditional maintenance approaches, such as reactive repairs and periodic inspections, have been found inadequate in addressing the dynamic challenges posed by aging infrastructure and evolving user expectations (2020). As such, Zhao et al. suggest proactive maintenance strategies, including condition-based monitoring, predictive analytics, and performance-driven asset management, have emerged as promising alternatives to enhance asset reliability, minimize downtime, and optimize life-cycle costs (2021). Implementing proactive maintenance practices may involve robust data collection mechanisms, advanced diagnostic tools, and integrated asset management systems capable of predicting asset deterioration and prescribing timely interventions.

Asset management frameworks provide structured methodologies and guidelines for managing transportation infrastructure assets holistically throughout their life cycles. The International Infrastructure Management Manual and similar standards offer comprehensive frameworks

encompassing asset inventory, risk assessment, life-cycle planning, performance monitoring, and decision support systems (Institute for Asset Management 2015). Integrating asset management principles into DOT guidelines facilitates informed decision-making, enhances resource allocation, and promotes the adoption of best practices in asset management (Li et al. 2022). Customizing asset management frameworks to accommodate the diverse needs and constraints of ancillary assets enhances their applicability and effectiveness in optimizing asset performance and achieving organizational objectives.

The process for selecting ancillary assets to include in a TAMP begins with establishing performance-based programs for their management and is also highlighted in the Handbook for Including Ancillary Assets in Transportation Asset Management Programs and presented in Figure 2.5 (Allen et al. 2019).

An initial step in managing any asset is to conduct data collection and inventory. Many point to technology to assist in this effort. Potential options include those presented by Allen et al. (2019), as seen in Figure 2.6.

Technological advancements, including Internet of Things (IoT) sensors, GIS, remote monitoring systems, and artificial intelligence (AI), have revolutionized asset management practices in transportation infrastructure (Chen et al. 2022). IoT-enabled sensors facilitate real-time data collection, enabling proactive maintenance interventions and optimizing asset performance. GIS platforms provide spatial intelligence for asset inventory management, condition assessment, and asset prioritization. AI and machine learning algorithms offer predictive capabilities for anticipating asset failures and prescribing preventive maintenance actions (Wang et al. 2021). Integrating diverse technological solutions into a cohesive asset management ecosystem enhances data interoperability, decision support capabilities, and organizational resilience.

Effective management of ancillary assets requires collaboration among diverse stakeholders, including government agencies, contractors, maintenance crews, regulatory bodies, and the public. Engaging stakeholders throughout the asset life cycle fosters transparency, accountability, and shared ownership of asset management objectives (Guo et al. 2020). Collaborative governance frameworks facilitate knowledge sharing, risk mitigation, and resource optimization, leveraging the collective expertise and resources of stakeholders (Cheng et al. 2021). Establishing communication channels, feedback mechanisms, and performance metrics promotes continuous improvement, community satisfaction, and public trust in transportation infrastructure management practices, but getting there takes an established level of maturity in managing these assets.

First, it is important to define Asset Management System Maturity Levels. The AASHTO TAM maturity scale includes the following levels (AASHTO 2013):

• Initial - No effective support from strategy, processes, or tools. There can be a lack of motivation to improve.

• Awakening - Recognition of a need and basic data collection. There is often a reliance on the heroic effort of individuals.
• Structured - Shared understanding, motivation, and coordination. Development of processes and tools.
• Proficient - Expectations and accountability drawn from asset management strategy, processes, and tools.
• Best Practice - Asset management strategies, processes, and tools are routinely evaluated and improved.

State DOTs implementing asset management of ancillary assets should expect to progress through these levels as they improve their management approach. Guidance for assisting in that progression can be found in national and international resources.

National Resources for Management of Ancillary Assets

One resource of interest is AASHTO’s Transportation Asset Management Guide. This resource illustrates that the core components of TAM include asset inventory, condition assessment, performance monitoring, risk analysis, and investment planning (AASHTO 2013; AASHTO 2025).

The guide describes how asset inventory involves cataloging and mapping transportation assets, such as roads, bridges, tunnels, and transit facilities, to establish a baseline for asset management activities. Condition assessment techniques are presented, ranging from visual inspections to advanced non-destructive testing methods, which are used to evaluate the physical condition and structural integrity of assets. Performance monitoring is explained as involving the collection and analysis of data on asset performance indicators, such as pavement condition, bridge load ratings, and transit ridership, to assess the effectiveness of maintenance strategies and identify areas for improvement. Risk analysis is illustrated as helping DOTs identify potential threats to asset performance, such as natural disasters, extreme weather events, and budgetary constraints, and develop mitigation strategies to enhance resilience. Finally, the guide presents investment planning that involves allocating resources efficiently to address the most critical needs and achieve the desired level of service.

Another resource of note is the Handbook for Including Ancillary Assets in Transportation Asset Management Programs (Allen et al. 2019). This handbook introduces a methodology designed to assist transportation asset owners and maintenance personnel in identifying critical assets, beyond just pavements and bridges, that align with their DOT’s missions and objectives. It emphasizes prioritizing asset classes and pinpointing relevant data crucial for a performance-oriented approach to asset management. The methodology is both comprehensive and adaptable, allowing customization to suit the specific requirements of each DOT. Tailored to aid state and local DOTs and other highway stakeholders, this handbook aims to guide them in determining essential assets and related data to support their overarching missions and objectives. It provides a broad understanding of asset management and performance management principles, offering valuable insights that can aid in complying with federal requirements, though it does not directly address these requirements or their fulfillment. Utilizing a performance-based management framework, the methodology facilitates the selection of asset information vital for decision-making regarding the installation, upkeep, enhancement, and replacement of ancillary assets. The methodology for selecting assets and data for inclusion in TAM programs is delineated into Asset Prioritization and Data Needs. Guidance is provided for establishing a ranking for incorporating assets into TAM programs in alignment with the DOT’s desired objectives. Guidance for establishing a rating system and relative weights provides DOTs with a pathway for objectively evaluating assets and considering the relative importance of different criteria. This handbook is a great starting point for those beginning to investigate the inclusion of ancillary assets in their TAM program.

Another resource is the Final Report for NCHRP Project 08-36, Task 114, Transportation Asset Management for Ancillary Assets (Rose et al. 2014). This report includes a literature review and provides guidance on the principles and practices of TAM for ancillary assets. It emphasizes the importance of recognizing the economic value of assets, achieving economic efficiency, and DOT stewardship. The document suggests a life-cycle asset management process, as seen in Figure 2.7, and discusses the integration of ancillary assets into enterprise asset management systems. It provides specific guidance on the life-cycle management of culverts, drainage systems, overhead sign and signal structures, high mast light poles, ITS equipment, network backbone, and sidewalks and curbs. The document also highlights the importance of comprehensive asset inventories, condition data collection, and life cycle management plans for ancillary assets. It references relevant literature, expertise, and survey responses from DOTs. The research is based on internationally accepted standards for asset management and is intended to supplement existing literature and guide DOTs in implementing asset management practices for ancillary assets.

A recently completed NCHRP Synthesis also serves as a valuable resource for ancillary asset management. NCHRP Synthesis 628: Ancillary Asset Data Stewardship and Models presents the current state of DOT practice related to data stewardship and data models for ancillary assets

(Nassereddine et al. 2024). This report focuses on 38 ancillary asset classes and reports on where and how data are collected by DOTs for these ancillary assets.

Additionally, the FHWA provides a vast collection of resources regarding the management of ancillary assets. These resources can be found at FHWA’s Asset Management website (https://www.fhwa.dot.gov/asset/), as previously mentioned. In FHWA-HIF-20-067: Transportation Asset Management Plans: Case Study 7 - Managing Assets Beyond Pavements and Bridges (Varma and Proctor 2020), assets are categorized into three tiers based on the value and complexity of management processes, where Tier 1 assets have the highest value and risk of financial impact if poorly managed, and Tier 3 assets have the lowest value and risk of negative impact for poor management. In this report, risk analysis is used to allocate resources to assets based on their risk and value. The report includes case studies of Minnesota DOT and Colorado DOT.

FHWA also provides a standalone case study, FHWA-HIF-23-020: Consideration of Risk in Managing Ancillary Assets: Minnesota Department of Transportation (MnDOT) Case Study (Zimmerman and Allen 2023). In this case study, MnDOT formulates its Asset Management Strategic Implementation Plan (AMSIP) with particular attention given to ancillary assets to ensure that the same performance-oriented management approach applied to pavements and bridges was extended to other assets. Early on, the MnDOT Asset Management Program Office identified the potential for reducing long-term costs associated with managing these assets by incorporating maintenance and operational expenses into asset management trade-off decisions. However, the implementation of a performance-based approach for ancillary assets relied heavily on MnDOT district staff. Hence, it was imperative to involve district staff in AMSIP development to clarify their roles and responsibilities in asset management. The AMSIP development objectives included achieving a balance between acquiring and managing asset data, considering associated risks and return on investment, enhancing the capability to assess tradeoffs between investment alternatives, and embedding asset management principles into MnDOT’s organizational culture.

MnDOT also recognized the potential risks if these objectives were left unaddressed. The subsequent sections of the case study delve into the efforts made to address these objectives and the resultant impact on mitigating the risks associated with inaction.

A final resource of note from FHWA is a website repository for the asset management plans of each DOT (https://www.fhwa.dot.gov/asset/plans.cfm).

International Resources for Management of Ancillary Assets

Public agencies across the globe have adopted various approaches to TAM, depending on their organizational structure, regulatory framework, funding mechanisms, and asset portfolios. In the United States, the FHWA and AASHTO have developed guidelines and best practices for implementing TAM at the state and local levels (AASHTO 2025). Similarly, in Europe, the European Commission has issued directives and standards to promote the adoption of TAM principles among member states (European Commission 2019). Common practices in TAM include the development of asset management plans, performance-based contracting, condition-based maintenance, and data-driven decision-making. Many DOTs have also embraced the concept of asset management maturity models to assess their organizational capabilities and identify areas for improvement.

Asset management principles, such as life-cycle management, risk assessment, and performance measurement, provide the foundation for managing transportation ancillary assets. Various conceptual frameworks and resources have been proposed to guide asset management practices, including the ISO 55000 family of International Standards for asset management (https://www.assetmanagementstandards.com/iso55000/). This set of standards was developed from a baseline of the British Standards Institution’s (BSI’s) Publicly Available Specification (PAS) 55 Specification for the Optimized Management of Physical Assets (https://theiam.org/knowledge-library/bsi-pas-55/). These resources emphasize the importance of aligning asset management strategies with organizational goals, prioritizing investments based on risk and performance, and optimizing resource allocation.

Highways England has developed a comprehensive asset management strategy to maintain and enhance the strategic road network in the United Kingdom. This strategy aligns with international best practices and emphasizes the importance of data-driven decision-making in asset management.

The Australian Transport Infrastructure Council (ATIC) promotes the adoption of asset management principles across Australia’s transport infrastructure sector. Through collaborative initiatives, such as the Australian Infrastructure Plan, ATIC seeks to improve asset performance, resilience, and sustainability. The New Zealand Transport Agency (NZTA) Asset Management Framework has developed an asset management framework to guide the management of New Zealand’s transport assets. This framework emphasizes the need for proactive maintenance, risk management, and stakeholder engagement to achieve long-term asset sustainability. Austroads provides an array of resources for asset management focused on Australia and New Zealand but internationally applicable (https://austroads.com.au/infrastructure/asset-management). A resource of note is the 15-part Guide to Asset Management (https://austroads.com.au/infrastructure/asset-management/guide-to-asset-management).

Finally, the Permanent International Association of Road Congresses (PIARC) World Road Association has a collection of resources on asset management (https://www.piarc.org/en/PIARC-knowledge-base-Roads-and-Road-Transportation/Road-Safety-Sustainability/Road-Assets-Management). They also publish a four-section Road Asset Management Manual that covers

assets beyond roads and bridges (https://www.piarc.org/en/PIARC-knowledge-base-Roads-and-Road-Transportation/Road-Safety-Sustainability/Road-Assets-Management).

Challenges and Future Directions

Despite the widespread adoption of TAM principles, several challenges present themselves in its implementation. One of the primary challenges is the finite amount of funding and resources that must be balanced across all the assets of a DOT, particularly in the face of aging infrastructure and growing maintenance backlogs. Limited data availability and quality pose challenges to effective asset management as DOTs toil to collect, integrate, and analyze disparate data sources. Moreover, other challenges can include organizational silos, bureaucratic inertia, and resistance to change. Regulatory constraints, political pressures, and public expectations further complicate decision-making processes and resource allocation. Additionally, transportation systems’ increasing complexity and interconnectedness require a holistic and interdisciplinary approach to asset management (FHWA 2007).

These same challenges affect the progress in managing ancillary assets. Resource constraints, budgetary limitations, and competing priorities often impede investment in proactive maintenance and technological upgrades (Zhang et al. 2020). Technological complexity, data interoperability issues, and cybersecurity concerns pose significant barriers to integrating advanced technologies into existing asset management systems (Zhou et al. 2019). Additionally, navigating regulatory frameworks and managing public expectations require careful coordination and stakeholder engagement (Wu et al. 2019). A multifaceted approach that encompasses policy reforms, capacity building, investment strategies, and stakeholder engagement initiatives is necessary to address these challenges.

Managing ancillary assets in transportation infrastructure necessitates a holistic approach integrating technological innovation, proactive maintenance strategies, stakeholder engagement, and asset management principles. By synthesizing insights from existing available resources and collective insights, DOT guidelines can provide a roadmap for optimizing transportation networks’ performance, resilience, and sustainability. Embracing emerging technologies, fostering collaboration among stakeholders, and addressing barriers are essential steps toward realizing the full potential of ancillary asset management in enhancing the safety, efficiency, and accessibility of transportation infrastructure (Allen et al. 2019).

Several emerging trends and technological advancements are poised to reshape the future of TAM. The proliferation of sensor technologies, IoT devices, and remote sensing technologies enables real-time monitoring of asset performance and condition, facilitating predictive maintenance and proactive decision-making (Chen et al. 2022). Machine learning algorithms, AI, and predictive analytics offer new opportunities for optimizing asset management strategies and allocating resources more efficiently. Furthermore, the concept of resilience-based asset management is gaining traction, emphasizing the importance of designing and maintaining infrastructure assets to withstand extreme events and weather impacts (Chacon-Hurtado et al. 2020). This future is quickly approaching, especially in regard to 3-D models and BIM as they relate to asset management.

In a recent report, CRP Special Release 4: Lifecycle BIM for Infrastructure: A Business Case for Project Delivery and Asset Management, the benefits of BIM for asset management include improved inspection, maintenance and operational costs, and time savings in data entry, data retrieval, safety compliance, and use for design. As many DOTs are already using 3D models, BIM is the next logical step for realizing even more benefits (Mitchell et al. 2023). Another step lies beyond the use of BIM. In the paper, “Practical Application of Digital Twins for Transportation Asset Data Management:

Case Example of a Safety Hardware Asset,” the case is made that digital twins of assets would benefit DOTs in cross-asset analysis and virtual testing of systems. This approach would be impactful for improving condition projections and predictive performance (Ammar et al. 2024).

Summary

In summary, TAM is a complex field that integrates theoretical frameworks, practical approaches, and cutting-edge technologies to enhance transportation assets’ performance, longevity, and sustainability. Incorporating ancillary assets into TAM presents significant prospects for bolstering transportation infrastructure systems’ resilience, efficiency, and effectiveness. Public agencies can surmount implementation challenges and fulfill their long-term asset management goals by harnessing advanced data analytics, predictive modeling, and collaborative decision-making. This literature review lays the groundwork for the subsequent presentation of survey findings and case examples gathered in this synthesis.