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Design of Piles for Downdrag
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program Aaron Budge Amalesh Jana Armin W. Stuedlein Johnathan D. Blanchard Richard A. CoffmanMany bridges are constructed in areas where there is compressible soil or liquefiable soil, which necessitates the consideration of downdrag forces and associated settlement. Downdrag for static and seismic conditions has increasingly placed greater demands on existing and new foundations and also led to higher construction costs. NCHRP Research Report 1112: Design of Piles for Downdrag presents procedures for determining downdrag loads used in the design of bridge piles. The NCHRP Research Report 1112 appendices are available as NCHRP Web-Only Document 398: Pile Design for Downdrag: Examples and Supporting Materials.
Pile Design for Downdrag: Examples and Supporting Materials
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program Aaron S. Budge Amalesh Jana Armin W. Stuedlein Johnathan D. Blanchard Richard A. CoffmanNCHRP Web-Only Document 398: Pile Design for Downdrag: Examples and Supporting Materials from TRB's National Cooperative Highway Research Program, provides appendices to NCHRP Research Report 1112: Design of Piles for Downdrag.
Mental Health, Wellness, and Resilience for Transit System Workers
by National Academies of Sciences, Engineering, and Medicine Transit Cooperative Research Program Koshy Koshy Lilly Derby Soumitra S. Bhuyan Samantha G. Farris Lori Zeller Sofie Rhoads Kyle Hearing Elias Frantz Orjuela Sandy BrennanTransit agency leadership must make a real and concerted effort to take the mental health and overall wellness of frontline workers more seriously. Leadership can play an important role by making a clear commitment and dedicating resources to address mental health, wellness, and resiliency at their agencies. Ultimately, this means that more funding and staff resources are needed to address barriers and to develop, implement, and support programs aimed at improving mental health, wellness, and resiliency. This includes staff dedicated to implementing and monitoring holistic wellness programs. TCRP Research Report 245: Mental Health, Wellness, and Resilience for Transit System Workers, from TRB’s Transit Cooperative Research Program, provides a detailed summary of common factors that influence the mental health, well-being, and resiliency of frontline transit workers and includes a range of solutions that transit agencies can implement to address them. Findings were determined using a mix of research methods, including multiple interviews and focus groups with frontline employees, transit agency management, and union leadership at two different points in the project. Supplemental to the report are a research brief and an implementation plan.
Transit Agencies Providing or Subsidizing Innovative Micromobility Projects: Legal Issues
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board Transit Cooperative Research Program Matthew W. DausThe use of scooters, bicycles, e-bikes, and other forms of micromobility has accelerated due to the COVID-19 pandemic, urban congestion, and parking restrictions. Some transit agencies provide or subsidize micromobility to bridge the gap between transit stops and destinations beyond a comfortable walking distance. While bikes and scooters are not new, micromobility has only recently been used in public transit. TCRP Legal Research Digest 61: Transit Agencies Providing or Subsidizing Innovative Micromobility Projects: Legal Issues, from TRB's Transit Cooperative Research Program, presents practices for transit agencies to consider when implementing shared-use micromobility systems to provide and support public transit, including accessibility, safety, regulation, jurisdiction, service quality, theft, insurance, liability, security, tracking, licensing, permitting, franchising, billing, maintenance, environmental justice, and compliance with civil rights laws. It also provides examples of cities regulating bike and scooter share programs and transit agencies participating in such programs.
Creating Self-Directed Resiliency Plans for General Aviation Airports
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board Airport Cooperative Research Program Mia Held Kim Fabend Mia Stephens Bridget Smith Lavanya Desai Alexis Lollar Amanda WittThere are nearly 3,000 general aviation (GA) airports that are important to the communities in which they operate and are key contributors to the successful network of the national airport system. GA airports are uniquely positioned assets in any community, and it is therefore essential for GA staff to understand, predict, and address shocks (such as airplane accidents, severe weather, and utility outages) and stressors (such as employment challenges, aging infrastructure, and climate change impacts) before they happen. ACRP Research Report 263: Creating Self-Directed Resiliency Plans for General Aviation Airports, from TRB’s Airport Cooperative Research Program, is a guide and toolkit that prepares GA airports to respond to, adapt to, and recover from all varieties of stressors and shocks while maintaining operations. Supplemental to the report are a flyer, an overview PowerPoint, and a set of associated tools and templates.
Implementing Machine Learning at State Departments of Transportation: A Guide
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program Kaan Ozbay Kelly Bare Sherif Ishak Mecit Cetin Matthew Samach Haley TownsendWithin the last two decades, Machine Learning (ML), the main subfield of Artificial Intelligence (AI), has gained significant momentum across all sectors, driven by a confluence of factors: exponential growth in data generation, advancements in data storage and computing, and innovations in algorithmic techniques. Most notably and recently, the proliferation of deep learning (DL) methods and generative AI tools (GATs) such as ChatGPT are revolutionizing the business landscape. In an era where data is pouring in from new sources, the pace of data growth is exceeding the pace at which state and local Departments of Transportation (DOTs) are able to use it. NCHRP Research Report 1122: Implementing Machine Learning at State Departments of Transportation: A Guide, from TRB's National Cooperative Highway Research Program, serves as both an education and a decision-making tool to assist state DOTs and other transportation agencies in identifying promising ML applications; assessing costs, benefits, risks, and limitations of different approaches; and building a data-driven organization conducive to capitalizing on and expanding ML capabilities in a broad spectrum of transportation applications. Along with supplemental files, there is an associated publication, NCHRP Web-Only Document 404: Implementing and Leveraging Machine Learning at State Departments of Transportation, which documents the overall research effort.
Uncrewed Aerial Systems Applications for Bridge Inspections: Element-Level Bridge Data Collection
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program Jeffrey Sams John Zuleger Ryan Stevens Matthew Hebdon Alicia McConnellInterest in and use of uncrewed aerial systems (UAS) have increased in the past 10 years. One application of considerable interest to transportation agencies and their private-sector partners is supplementing traditional highway bridge inspection data-collection tools. They have shown particular interest in performing safety inspections of bridge elements that are typically costly for bridge owners. By using UAS, the bridge superstructure and substructure can be assessed without requiring lanes of traffic to close or exposing inspectors to traffic. NCHRP Research Report 1114: Uncrewed Aerial Systems Applications for Bridge Inspections: Element-Level Bridge Data Collection, from TRB’s National Cooperative Highway Research Program, presents strategies for using UAS for collecting element-level data during bridge inspections. Supplemental to the report are a survey, rankings, implementation memo, and roadmap.
Visualization for Public Involvement
by Transportation Research Board National Academies of Sciences, Engineering, and Medicine National Cooperative Highway Research Program Pamela Lebeaux Robin ChristiansVisualization methods have long been integral to the public involvement process for transportation planning and project development. From well-established methods such as conceptual sketches or photo simulations to the latest immersive technologies, state departments of transportation (DOTs) recognize that visualizations can significantly increase public understanding of a project’s appearance and physical impacts. Emerging methods such as interactive three-dimensional environments, virtual reality, and augmented reality can dramatically enhance public understanding of transportation options and design concepts. NCHRP Synthesis 632: Visualization for Public Involvement, from TRB’s National Cooperative Highway Research Program, documents state DOT practices of visualization for public involvement throughout the life cycle of plans, programs, and projects.
Examination of Transit Agency Coordination with Electric Utilities
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board Transit Cooperative Research Program Lisa JerramPublic transit agencies across the United States are transitioning conventional bus fleets to battery electric buses (BEBs). This transition requires large investments in charging infrastructure as well as new demands on the power grid, which provides opportunities for partnership with electric utilities to upgrade grid supply and energy loads, and also to reduce costs during peak load. TCRP Synthesis 175: Examination of Transit Agency Coordination with Electric Utilities, from TRB’s Transit Cooperative Research Program, provides practitioners and operational staff at public transit bus agencies and electric utilities with the state of current practices by agencies and utilities that are collaborating on BEB planning and deployments.
Understanding Airport Air Quality and Public Health Studies Related to Airports, Second Edition
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board Airport Cooperative Research Program Margaret Zenke Cory Cook Lige Han Charlotte O’Donnell Maureen MullenThe communities surrounding airports have become increasingly aware of airport emissions and potential impacts of those emissions on local air quality and public health. Those concerns along with growth in airport operations have spurred the need for airport operators to more fully understand the potential for health impacts related to airport operations and to develop better information and methods to share this information with the public. ACRP Web-Only Document 62: Understanding Airport Air Quality and Public Health Studies Related to Airports, Second Edition, from TRB’s Airport Cooperative Research Program, evaluates and updates the existing body of knowledge on air quality and public health studies related to airports to help airport operators better understand and respond to airport-related air quality and public health concerns. Supplement to the document is an interactive version of Appendix A from the report that lists relevant peer-reviewed publications.
Law Enforcement Use of Probabilistic Genotyping, Forensic DNA Phenotyping, and Forensic Investigative Genetic Genealogy Technologies: Proceedings of a Workshop
by National Academies of Sciences, Engineering, and Medicine Division on Engineering and Physical Sciences Division of Behavioral and Social Sciences and Education Computer Science and Telecommunications Board Committee on Law and JusticeTo better understand key considerations around law enforcement use of advanced forensic DNA technologies, the Committee on Law and Justice and the Computer Science and Telecommunications Board at the National Academies of Sciences, Engineering, and Medicine held a workshop titled "Law Enforcement Use of Probabilistic Genotyping, Forensic DNA Phenotyping, and Forensic Investigative Genetic Genealogy Technologies." The workshop was organized in response to Executive Order 14074, issued in May 2022, and was held on March 13 and 14, 2024. The order focused on advancing effective, accountable policing, as well as criminal justice practices around algorithmic approaches to policing; it directed the National Academies to hold a workshop to explore the different approaches. The workshop focused on three specific advanced forensic DNA practices: probabilistic genotyping, forensic DNA phenotyping, and forensic investigative genetic genealogy. This publication summarizes the presentations and discussion of the workshop.
Considering Greenhouse Gas Emissions and Climate Change in Environmental Reviews: Conduct of Research Report
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program Zamurs and Associates, LLC Inch And Meter Parametrix Georgetown Climate CenterMany state departments of transportation (DOTs) are working to incorporate the treatment of greenhouse gas (GHG) emissions, climate change effects, or both in project planning and environmental reviews. There is a wide range of experience, with some states working hard to integrate all of their activities (including environmental review) into a unified, agency-wide treatment of climate change while others are just beginning their efforts. NCHRP Web-Only Document 400: Considering Greenhouse Gas Emissions and Climate Change in Environmental Reviews: Conduct of Research Report supplements the resources and guidance for state DOTs on addressing climate change effects and GHG emissions provided by NCHRP WebResource 3: GHG Emissions and Climate Change in Environmental Reviews. Supplemental to NCHRP Web-Only Document 400 is a fact sheet that summarizes the essential findings of the project and provides an overview of the WebResource, as well as an implementation memo that identifies implementation pathways for the project.
Planning for Future Electric Vehicle Growth at Airports
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board Airport Cooperative Research Program Sara Kaplan Angela Archibeque Krista Robertson Maranda Thompson Kate Andrus Mia Stephens Grant Bennett Rex HazeltonBecause of the diversity of charging needs at airports and the varied policy environments in which airports operate, no single roadmap describes how to best install electric vehicle charging. Furthermore, an airport may use multiple approaches to owning and operating charging infrastructure. To help simplify this complex space, this planning guide categorizes charging into eight use cases. ACRP Web-Only Document 61: Planning for Future Electric Vehicle Growth at Airports, from TRB’s Airport Cooperative Research Program, is designed as a primer to help educate airport staff and practitioners on the technologies and processes associated with charging infrastructure. The guide was developed in Phase I of a project that will include additional products in Phase II.
Diagnostic Assessment and Countermeasure Selection: A Toolbox for Traffic Safety Practitioners
by John L. Campbell Transportation Research Board National Academies of Sciences, Engineering, and Medicine National Cooperative Highway Research Program Behavioral Traffic Safety Cooperative Research Program Ingrid B. Potts Darren J. Torbic Audra K. Fraser Chris Monk Liberty Hoekstra-AtwoodSuccessful safety management practices require a thorough understanding of factors contributing to motor vehicle crashes. Continuous advancements in data-driven safety analysis, as well as the countermeasures and technologies available to address crashes, create challenges in maintaining a safety workforce proficient in the state of the practice. In many cases, agencies continue to use approaches such as descriptive statistics and anecdotal information to perform the diagnostic assessment without a thorough understanding of the expectations for a given context or road type. NCHRP Research Report 1111/BTSCRP Research Report 12: Diagnostic Assessment and Countermeasure Selection: A Toolbox for Traffic Safety Practitioners, from TRB's National Cooperative Highway Research Program and Behavioral Traffic Safety Cooperative Research Program, presents a toolbox to help highway safety practitioners diagnose contributing factors leading to crashes for use in selecting appropriate countermeasures. Supplemental to the report are a Conduct of Research Report, an Implementation of Findings, and a presentation.
Resolving Construction Disputes: Review of State DOT Processes
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program Michael C. LoulakisCommercial disputes among owners, contractors, and subcontractors on construction projects are a fact of life, regardless of how hard parties might try to avoid them. Sometimes these disputes get resolved quickly at the project level, but sometimes the dispute is handled through litigation. NCHRP Legal Research Digest 92: Resolving Construction Disputes: Review of State DOT Processes, from TRB's National Cooperative Highway Research Program, aims to build a better understanding of what state departments of transportation (DOTs) are doing in terms of alternative dispute resolution (ADR) processes and reviews state DOT practices for construction disputes.
Pay and Working Conditions in the Long-Distance Truck and Bus Industries: Assessing for Effects on Driver Safety and Retention
by National Academies of Sciences, Engineering, and Medicine Division of Behavioral and Social Sciences and Education Transportation Research Board Committee on National Statistics Consensus and Advisory Studies Committee for a Study of the Impacts of Alternative Compensation Methods on Truck Driver Retention and Safety PerformanceFor-hire trucking—as opposed to in-house private carriers that transport the goods of their parent company—is a large and heterogeneous industry with considerable variability in carrier sizes, operational structures, and freight markets served. For this sector, the Federal Motor Carrier Safety Administration should explore opportunities for leveraging research and data collection that may be planned and programmed for other purposes to help regulators, researchers, and industry examine the potential effects of driver compensation and work conditions on the safe driving behavior and performance of long-distance for-hire truck drivers. This is among the recommendations in TRB Special Report 355: Pay and Work Conditions in the Long-Distance Truck and Bus Industries: Assessing for Effects on Driver Safety and Retention, from the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. The report examines—in response to a request from the U.S. Congress—the impacts of various methods of driver compensation on safety and driver retention, including hourly pay, payment for detention time, and other payment methods used in the industry.
Bridge Railing Design Requirements
by Transportation Research Board Thomas P. Murphy National Cooperative Highway Research Program Mark Bloschock Marcus Galvan Ronald K. Faller Andrew E. Loken Scott K. Rosenbaugh Joshua S. Steelman Maria D. Lopez John M. HoltAs of January 1, 2020, all new and replacement bridge rails installed on the National Highway System are required to conform to the requirements stipulated in the AASHTO Manual for Assessing Safety Hardware [MASH], 2nd edition (2016). NCHRP Research Report 1109: Bridge Railing Design Requirements, from TRB's National Cooperative Highway Research Program, presents an update to bridge railing design requirements to ensure consistency with the state of knowledge. The update incorporates the recommendations from NCHRP Research Report 1024: Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance and NCHRP Research Report 1078: MASH Railing Load Requirements for Bridge Deck Overhang. An appendix to the report presents design examples for railings and deck overhangs.
Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide
by Transportation Research Board National Academies of Sciences, Engineering, and Medicine Scott S. Washburn National Cooperative Highway Research Program Bastian Schroeder Jorge Barrios Ana Moreno Sajid Raza Ahmed Al-KaisyRural highways account for a significant portion of the National Highway System and serve many vital mobility purposes. The Highway Capacity Manual, the standard reference for traffic analysis methodologies, contains analysis methodologies for all of the individual segments or intersections that may constitute a rural highway; however, it does not include a methodology or guidelines for connecting the individual roadway segments into a connected, cohesive, facility-level analysis. NCHRP Research Report 1102: Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide, from TRB’s National Cooperative Highway Research Program, presents a guide for traffic analysis of rural highways that connects the individual highway segments into a connected, cohesive, facility-level analysis. Supplemental to the report is NCHRP Web-Only Document 392: Developing a Guide for Rural Highways: Reliability and Quality of Service Evaluation Methods.
Development of a MASH Barrier to Shield Pedestrians, Bicyclists, and Other Vulnerable Users from Motor Vehicles
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program James Kovar Roger Bligh Shawn Turner Sun Hee Park Chiara Silvestri DobrovolnyAs the number of pedestrians, bicyclists, and users of other active transportation modes continues to grow in the United States, state departments of transportation and other transportation agencies are seeking to improve how these users are accommodated on or adjacent to our nation?s roadways. NCHRP Research Report 1116: Development of a MASH Barrier to Shield Pedestrians, Bicyclists, and Other Vulnerable Users from Motor Vehicles, from TRB's National Cooperative Highway Research Program, provides a detailed design for a crashworthy roadside barrier system for use alongside high-speed roadways that also addresses the needs of nonmotorized users of adjacent multiuse facilities. Supplemental to the report are: Survey, Crash Test Data, and Supporting Certification Documents: Appendices A, C, D, G, H, and I; Technical Drawings and Information for FHWA Eligibility Filing: Appendices B, E, F, and J; Technical Memo; PowerPoint Presentation; and NCHRP 22-37 Composite Crash Test Video.
Developing a Guide for Rural Highways: Reliability and Quality of Service Evaluation Methods
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program Bastian Schroeder Jorge Barrios Ana Moreno Sajid Raza Ahmed Al-Kaisy Scott S. WashburnTransportation agencies are charged with monitoring, maintaining, and improving rural highways of regional or statewide importance. NCHRP Web-Only Document 392: Developing a Guide for Rural Highways: Reliability and Quality of Service Evaluation Methods, from TRB's National Cooperative Highway Research Program, is a supplement to NCHRP Research Report 1102: Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide.
Transporting Freight in Emergencies: A Guide on Special Permits and Weight Requirements
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program Jack Merritt Curtis Morgan Jeffery Warner David Bierling Bradley Trefz Sushant SharmaCommercial vehicles delivering consumer goods must observe the applicable weight requirements and seek permits for oversize loads. Due to the COVID-19 pandemic, significant changes accelerated in e-commerce, adding pressure for the freight community to deliver goods directly to consumers in an environment of uncertainty where consumers were buying in bulk, exhausting supplies of common and necessary goods. On top of consumer disruptions to the freight system, truckers urgently had to make deliveries of much-needed, pandemic-related supplies. NCHRP Research Report 1115: Transporting Freight in Emergencies: A Guide on Special Permits and Weight Requirements, from TRB’s National Cooperative Highway Research Program, provides a guide to state departments of transportation to consider options to better anticipate and respond to state and federal emergencies, specifically related to the movement of overweight commercial vehicles carrying emergency commodities within a state or across a region. Supplemental to the report are the following: 1. NCHRP WOD 397: Developing a Guide for Transporting Freight in Emergencies: Conduct of Research 2. Implementation Plan 3. Research Presentation
Developing a Guide for Transporting Freight in Emergencies: Conduct of Research
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program Jack Merritt Curtis Morgan Jeffery Warner David Bierling Bradley Trefz Sushant SharmaCommercial vehicles delivering consumer goods must observe the applicable weight requirements and seek permits for oversize loads. NCHRP WOD 397: Developing a Guide for Transporting Freight in Emergencies: Conduct of Research, from TRB’s National Cooperative Highway Research Program, is a supplement to NCHRP Research Report 1115: Transporting Freight in Emergencies: A Guide on Special Permits and Weight Requirements.
Evaluating Crashworthiness of Sign Supports and Breakaway Luminaire Poles: Appendices
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program Cing-Dao Steve Kan Fadi Tahan Dhafer Marzougui Mohammadreza Rajaee Riley Ruskamp Chen Fang Cody Stolle Ronald Faller Robert Bielenberg Mojdeh Asadollahi PajouhRoadside safety features such as luminaire poles and sign supports are evaluated for crashworthiness using the AASHTO Manual for Assessing Safety Hardware (MASH) guidelines for crash testing. The updated preliminary testing protocols provide guidelines for evaluating families of related sign support and breakaway luminaire pole devices. NCHRP Web-Only Document 405: Evaluating Crashworthiness of Sign Supports and Breakaway Luminaire Poles: Appendices, from TRB’s National Cooperative Highway Research Program, is supplemental to NCHRP Research Report 1123: Guidelines for Evaluating Crashworthiness of Sign Supports and Breakaway Luminaire Poles.
Mobile Devices as a Tool for Digitized Project Documentation and Inspection
by National Academies of Sciences, Engineering, and Medicine Transportation Research Board National Cooperative Highway Research Program Ryan Grith Gabriel Dadi Nisa Zahin Bassam Ramadan Hala NassereddineConsumer-grade mobile devices including smartphones, tablets, peripheral devices, and Rovers?are increasingly used as innovative tools in construction project delivery, documentation, and inspection. Advances in camera technology combined with increased accuracy in geolocation, graphical displays, and LiDAR abilities provide a powerful construction technology that is also widely accessible and used by most construction professionals on jobsites. NCHRP Synthesis 635: Mobile Devices as a Tool for Digitized Project Documentation and Inspection, from TRB’s National Cooperative Highway Research Program, documents practices of state departments of transportation for using mobile devices to support digitized project delivery, documentation, and inspection.
Implementing and Leveraging Machine Learning at State Departments of Transportation
by Kaan Ozbay Transportation Research Board National Academies of Sciences, Engineering, and Medicine National Cooperative Highway Research Program Haley Townsend Matthew Samach Sherif Ishak Mecit CetinThere is enormous potential for Machine Learning (ML) to transform state Departments of Transportation (DOTs), by strategizing and deploying ML solutions that improve transportation safety, efficiency, equity, and sustainability. NCHRP Web-Only Document 404: Implementing and Leveraging Machine Learning at State Departments of Transportation, from TRB’s National Cooperative Highway Research Program, is the conduct of research report for NCHRP Project 23-16 and documents the state of the art and state of the practice on ML; presents case studies on ML applications; and compiles ML tools and sample ML applications. NCHRP Web-Only Document 404 is a supplement to NCHRP Research Report 1122: Implementing Machine Learning at State Departments of Transportation: A Guide.