State departments of transportation (DOTs) and local agencies are utilizing uncrewed aircraft systems (UAS) in day-to-day operations such as traffic incident management, mapping, bridge and structure inspections, geographic information systems, environmental requirements, and a variety of other uses. Additionally, external developments on package delivery via UAS and advanced air mobility (AAM) raise issues about their safe operation over state and local rights-of-way and needed ground infrastructure and airspace management.
NCHRP Research Report 1147: Implementation of Uncrewed Aircraft Systems Operational Capabilities: A Guide, from TRB's National Cooperative Highway Research Program, presents state-of-the-art information and provides recommendations based on the latest developments in UAS and AAM technologies, along with practical use cases and applications. The findings will serve as a valuable resource for state DOTs and other public transportation agencies.
Supplemental to this report is NCHRP Web-Only Document 424: Uncrewed Aircraft Systems Operational Capabilities.
128 pages
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ISBN Paperback: 0-309-99287-7
ISBN Ebook: 0-309-99288-5
DOI:
https://doi.org/10.17226/29132
National Academies of Sciences, Engineering, and Medicine. 2025. Implementation of Uncrewed Aircraft Systems Operational Capabilities: A Guide. Washington, DC: The National Academies Press.
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State departments of transportation (DOTs) are self-reporting the use of uncrewed aircraft systems (UAS) across various use cases for data collection, asset inspection, and incident response. The maturity of implementation of UAS across state DOTs varies from initial exploration of the technologies to robust UAS programs facilitating daily use of the tool across multiple use cases.
NCHRP Web-Only Document 424: Uncrewed Aircraft Systems Operational Capabilities, from TRB's National Cooperative Highway Research Program, is a supplemental report to NCHRP Research Report 1147: Implementation of Uncrewed Aircraft Systems Operational Capabilities: A Guide. The research focuses on analyzing the challenges associated with maturing UAS programs and strategies to mitigate these difficulties and on providing resources to transportation agencies to gain a better understanding of UAS and advanced air mobility (AAM).
123 pages
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ISBN Ebook: 0-309-99291-5
DOI:
https://doi.org/10.17226/29133
National Academies of Sciences, Engineering, and Medicine. 2025. Uncrewed Aircraft Systems Operational Capabilities. Washington, DC: The National Academies Press.
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In 2019, the American Intercity Bus Riders Association created the National Intercity Bus Atlas, a database of intercity bus transit services in the United States. The Intercity Bus Atlas was developed to facilitate the promotion of intercity bus use by providing comprehensive service provider, route, and scheduling information in a public-facing online platform. Before this, there had been no publicly available national clearinghouse, list, or map of intercity bus services.
NCHRP Research Report 1150: Implementation of the National Intercity Bus Atlas, from TRB's National Cooperative Highway Research Program, documents that the development of the data framework for mapping. Technical challenges and hesitancy by some private carriers to share certain operating data resulted in several key information gaps. The report offers suggested future improvements to the atlas such as including more service characteristics and strategies to address data collection challenges.
60 pages
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ISBN Paperback: 0-309-99186-2
ISBN Ebook: 0-309-99187-0
DOI:
https://doi.org/10.17226/29119
National Academies of Sciences, Engineering, and Medicine. 2025. Implementation of the National Intercity Bus Atlas. Washington, DC: The National Academies Press.
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There are several ways the presence of water contributes to damage in asphalt and composite (asphalt surfaces on concrete) pavements. Being able to limit the damage to these pavement structures caused by the presence of water begins with an understanding of the sources of water.
NCHRP Web-Only Document 433: Limiting Damage to Flexible and Composite Pavements due to the Presence of Water: Guidelines, from TRB's National Cooperative Highway Research Program, presents successful practices that have been used by highway agencies throughout the United States in minimizing the adverse effects of moisture on flexible and composite pavement structures at all of the stages of a pavement’s life, from design to construction, maintenance and preservation, and rehabilitation.
163 pages
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ISBN Ebook: 0-309-99463-2
DOI:
https://doi.org/10.17226/29201
National Academies of Sciences, Engineering, and Medicine. 2025. Limiting Damage to Flexible and Composite Pavements due to the Presence of Water: Guidelines. Washington, DC: The National Academies Press.
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Temperature, precipitation, cloud cover, freezing index, and other environmental conditions can have a significant effect on flexible and rigid pavement performance, both in actuality and in terms of what is modeled. These factors affect how the pavement layer materials behave when responding to traffic loadings and when subjected to environmental loadings.
NCHRP Research Report 1151: Mechanistic–Empirical Pavement Design Model: Enhancements of Climatic Inputs, from TRB's National Cooperative Highway Research Program, explores how to improve climatic inputs and related models that can be implemented by transportation agencies.
98 pages
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ISBN Paperback: 0-309-99256-7
ISBN Ebook: 0-309-99257-5
DOI:
https://doi.org/10.17226/29125
National Academies of Sciences, Engineering, and Medicine. 2025. Mechanistic-Empirical Pavement Design Model: Enhancements of Climatic Inputs. Washington, DC: The National Academies Press.
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The Every Day Counts (EDC) Program is a key component of the Technology and Innovation Deployment Program (TIDP) within the U.S. Federal Highway Administration at the U.S. Department of Transportation. It works to increase the use of new technologies and approaches that can speed the planning and completion of transportation projects.
CRP Special Release 5: Evaluation of the Every Day Counts Program, from the Transportation Research Board, provides a summary of the EDC Program evaluation conducted from 2023 through 2024.
68 pages
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ISBN Paperback: 0-309-73353-7
ISBN Ebook: 0-309-73354-5
DOI:
https://doi.org/10.17226/28871
National Academies of Sciences, Engineering, and Medicine. 2025. Evaluation of the Every Day Counts Program. Washington, DC: The National Academies Press.
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The asphalt pavement industry has a long history of using recycled materials in asphalt mixtures to achieve engineering, economic, or environmental benefits. One example is reclaimed asphalt pavement, which is one of the most recycled materials in the United States.
NCHRP Research Report 1143: Evaluation of Post-Consumer Recycled Plastics in Asphalt Mixtures via the Dry Process, from TRB's National Cooperative Highway Research Program, evaluates the impact of post-consumer recycled plastics on the performance properties of asphalt mixtures when added using the dry process.
150 pages
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ISBN Paperback: 0-309-73331-6
ISBN Ebook: 0-309-73332-4
DOI:
https://doi.org/10.17226/28867
National Academies of Sciences, Engineering, and Medicine. 2025. Evaluation of Post-Consumer Recycled Plastics in Asphalt Mixtures via the Dry Process. Washington, DC: The National Academies Press.
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Recognizing the value of managing a broader range of assets beyond pavements and bridges, many state departments of transportation (DOTs) are developing dynamic inventories of various ancillary assets in their Transportation Asset Management Plans. Examples include hydraulic structures like culverts and drainage systems and overhead sign and signal structures and signal systems.
NCHRP Synthesis 647: Management Practices for Ancillary Transportation Assets, from TRB's National Cooperative Highway Research Program, documents how state DOTs manage ancillary transportation assets, including those managed via performance-based approaches.
166 pages
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ISBN Paperback: 0-309-73498-3
ISBN Ebook: 0-309-73499-1
DOI:
https://doi.org/10.17226/29059
National Academies of Sciences, Engineering, and Medicine. 2025. Management Practices for Ancillary Transportation Assets. Washington, DC: The National Academies Press.
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Erosion and sediment control (ESC) practices are used to prevent soil loss and reduce sediment-laden stormwater runoff. They could be either temporary or permanent and could be used in construction, maintenance, and operations practices.
NCHRP Synthesis 643: Use of Sustainable Materials for Erosion and Sediment Control Practices, from TRB's National Cooperative Highway Research Program, documents the current use of plastics in ESC practices across state departments of transportation as well as state DOTs’ policies and plans to reduce or eliminate the use of plastics for ESC practices.
90 pages
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ISBN Paperback: 0-309-73423-1
ISBN Ebook: 0-309-73424-X
DOI:
https://doi.org/10.17226/29034
National Academies of Sciences, Engineering, and Medicine. 2025. Use of Sustainable Materials for Erosion and Sediment Control Practices. Washington, DC: The National Academies Press.
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Planning and operating transportation systems involves the exchange of large volumes of data that must be shared between partnering transportation agencies, private-sector interests, travelers, and intelligent devices such as traffic signals, ramp meters, and connected vehicles.
NCHRP Research Report 1121: Data Integration, Sharing, and Management for Transportation Planning and Traffic Operations, from TRB's National Cooperative Highway Research Program, presents tools, methods, and guidelines for improving data integration, sharing, and management practices through case studies, proof-of-concept product developments, and deployment assistance.
290 pages
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paperback
ISBN Paperback: 0-309-73229-8
ISBN Ebook: 0-309-73227-1
DOI:
https://doi.org/10.17226/28690
National Academies of Sciences, Engineering, and Medicine. 2025. Data Integration, Sharing, and Management for Transportation Planning and Traffic Operations. Washington, DC: The National Academies Press.
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Many existing highways were originally constructed without stormwater control facilities, prompting several state departments of transportation (DOTs) to retrofit these highway facilities with improved treatment and flow control systems. To implement watershed-based strategies more cost effectively, some DOTs have explored partnerships with third-party entities.
NCHRP Synthesis 654: Stormwater Retrofit Programs and Practices Through Third-Party Partnerships, from TRB's National Cooperative Highway Research Program, documents the varied approaches taken by state DOTs on stormwater retrofit partnerships with third parties.
104 pages
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ISBN Paperback: 0-309-99220-6
ISBN Ebook: 0-309-99221-4
DOI:
https://doi.org/10.17226/29106
National Academies of Sciences, Engineering, and Medicine. 2025. Stormwater Retrofit Programs and Practices Through Third-Party Partnerships. Washington, DC: The National Academies Press.
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State departments of transportation (DOTs) undertake numerous bridge replacements annually. Specific replacements present unique challenges among these projects due to location restrictions, mobility implications, design characteristics, and environmental constraints.
NCHRP Synthesis 645: Construction Strategies and Techniques for Planned Bridge Replacements in Complex Scenarios, from TRB's National Cooperative Highway Research Program, documents practices and decision-making used by state DOTs for planned bridge replacements in complex scenarios.
104 pages
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ISBN Paperback: 0-309-73403-7
ISBN Ebook: 0-309-73404-5
DOI:
https://doi.org/10.17226/29029
National Academies of Sciences, Engineering, and Medicine. 2025. Construction Strategies and Techniques for Planned Bridge Replacements in Complex Scenarios. Washington, DC: The National Academies Press.
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Open-book negotiations for determining construction pricing for transportation agencies can enhance cost certainty, optimize risk allocation, and ultimately lead to more efficient project delivery. In a survey of 42 state departments of transportation (DOTs), key insights arise in how agencies negotiate construction costs post-award, collaborate with independent cost estimators, and manage project contingencies. Additionally, case examples reveal the critical role of trust and transparency in ensuring fair and reasonable guaranteed maximum prices.
NCHRP Synthesis 653: Open-Book Pricing Practices for Construction Manager/General Contractor and Progressive Design-Build Projects, from TRB's National Cooperative Highway Research Program, explores the complexities of alternative project delivery methods for state DOTs, with a focus on transparency, risk management, and cost negotiation.
140 pages
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ISBN Paperback: 0-309-73576-9
ISBN Ebook: 0-309-73577-7
DOI:
https://doi.org/10.17226/29084
National Academies of Sciences, Engineering, and Medicine. 2025. Open-Book Pricing Practices for Construction Manager/General Contractor and Progressive Design-Build Projects. Washington, DC: The National Academies Press.
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Transportation Insights 6: 7th International Conference on Women and Gender in Transportation presents the discussions and insights from a conference in Irvine, CA, from September 9 to 11, 2024.
87 pages
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ISBN Ebook: 0-309-99261-3
DOI:
https://doi.org/10.17226/29126
National Academies of Sciences, Engineering, and Medicine. 2025. 7th International Conference on Women and Gender in Transportation. Washington, DC: The National Academies Press.
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State departments of transportation (DOTs) have effective procurement processes for highway construction but lag in acquiring new business technologies. As they invest in advanced solutions for communications, asset management, and human resources, they aim to leverage artificial intelligence and cloud-based big data tools. However, traditional procurement methods typically relied on by state DOTs focus on individual purchases rather than long-term goals and often fall short in addressing the growing complexity of these systems and evolving customer needs. This can create challenges in acquiring technological products and services.
NCHRP Research Report 1145: Practices for Transportation Agency Procurement and Management of Advanced Technologies, from TRB's National Cooperative Highway Research Program, presents a guide that includes successful strategies and practices for procuring new and innovative transportation system technologies.
90 pages
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ISBN Paperback: 0-309-73547-5
ISBN Ebook: 0-309-73548-3
DOI:
https://doi.org/10.17226/29072
National Academies of Sciences, Engineering, and Medicine. 2025. Practices for Transportation Agency Procurement and Management of Advanced Technologies. Washington, DC: The National Academies Press.
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Section 106 of the National Historic Preservation Act requires federal agencies, including the U.S. Federal Highway Administration, to take into account the effects of their programs and projects listed in or eligible for listing in the National Register of Historic Places.
NCHRP Web-Only Document 412: Creating a Handbook for Successful No-Effect and No-Adverse-Effect Section 106 Determinations, from TRB’s National Cooperative Highway Research Program, is a supplement to NCHRP Research Report 1133: Preparing Successful No-Effect and No-Adverse-Effect Section 106 Determinations: A Handbook for Transportation Cultural Resource Practitioners.
311 pages
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ISBN Ebook: 0-309-73431-2
DOI:
https://doi.org/10.17226/29036
National Academies of Sciences, Engineering, and Medicine. 2025. Creating a Handbook for Successful No-Effect and No-Adverse-Effect Section 106 Determinations. Washington, DC: The National Academies Press.
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The 1926 Air Commerce Act established which aspects of aviation the federal government would and would not regulate. Although it was understood that standardization created safety and reliability, the Act did not create standards for airports. Instead, the Department of Commerce created a voluntary rating system aimed to provide objective guidance to municipalities and private companies that wanted to construct or improve facilities.
ACRP Legal Research Digest 48: Legal Issues Concerning the Safety and Security of General Aviation Airports, from TRB's Airport Cooperative Research Program, explores legal issues related to safety and security at general aviation airports, with a focus on state regulatory requirements for general aviation airports.
84 pages
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ISBN Paperback: 0-309-73543-2
ISBN Ebook: 0-309-73544-0
DOI:
https://doi.org/10.17226/29071
National Academies of Sciences, Engineering, and Medicine. 2025. Legal Issues Concerning the Safety and Security of General Aviation Airports. Washington, DC: The National Academies Press.
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Transportation modeling applications can be divided into two categories: travel demand forecasting and operational modeling. Demand forecasting predicts future traffic volumes for long-term infrastructure investments; operational modeling focuses on specific problems at a near-term or finer level of detail (such as for improving the traffic signal timing along a corridor, identifying the causes of an existing bottleneck, assessing the mobility impacts of a planned construction project, or decision-making on alternative selection).
NCHRP Synthesis 650: Practices for Operational Traffic Simulation Models, from TRB's National Cooperative Highway Research Program, documents state department of transportation processes and procedures for the use of operational traffic simulation models.
192 pages
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ISBN Paperback: 0-309-73560-2
ISBN Ebook: 0-309-73561-0
DOI:
https://doi.org/10.17226/29076
National Academies of Sciences, Engineering, and Medicine. 2025. Practices for Operational Traffic Simulation Models. Washington, DC: The National Academies Press.
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