The US Transportation Collection consists of documents from across all transportation modes with specific focus on research reports from US DOT, state DOTs, and other transportation organizations.
Bookmark this collection: https://rosap.ntl.bts.gov/collection_ust or https://doi.org/10.21949/1530857.
The objective of this research is to expand and validate decision-making tools and best practices for mass concrete thermal management, integrating emerging cementitious materials. Building on the foundations established in previous phases, this project evaluates an expanded range of concrete mix designs—including Type IL cement and reclaimed fly a
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The objective of this study was to investigate the effectiveness of using ultra-high toughness (UHT) steel in bridges to improve the structural reliability for the fracture limit state. The work included literature review, identification of candidate UHT steels, initial material characterization of all candidate steels, in-depth material characteri
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Cities are dynamics centers of modern life, continually evolving through both growth and decline. While agglomeration and associated amenities are benefits of growing global urbanization, congestion and the resulting pollution, delays, and inequity are common negative externalities of increasing urbanization. This study evaluates growth and congest
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Tied arch bridges represent a vital component of the nation's infrastructure, valued for their structural efficiency and aesthetic qualities. These bridges rely on arch ribs to transfer vertical loads into horizontal thrusts, which are counteracted by the tie beams (TBs) acting in axial tension. In addition to this axial tension, TBs are also subje
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Mechanically stabilized earth (MSE) walls often contain galvanized steel reinforcement. Because galvanized steel eventually corrodes, however, the corrosion process must be closely monitored to accurately determine where structures are in their life cycle and to improve specifications to lengthen the lifespan of future MSE walls. This report is a c
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Tow truck operators are exposed to traffic when responding to incidents. Stalled vehicles on the highway can hinder safety and operations on the highway and can create a risk of secondary incidents. Fast and effective removal of stalled vehicles on the highway can improve traffic operations and safety for tow truck operators and all users of the tr
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The research team evaluated 59 bridges in diverse types, age groups, and geographical locations. Best practices of the technologies were developed and summarized in inspection protocols and guidelines using commercial drones, structural crawlers, and hybrid uncrewed vehicles. Bridge inspection protocols and guidelines are presented in three parts:
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This study explores the effects of pandemic-related trucking relaxations on freight safety in Oregon. A historical review of trucking relaxations before and during the pandemic is conducted and compared. Using traffic volume levels and key pandemic dates, three time periods were chosen for analysis: (1) pre-pandemic, (2) a low VMT pandemic period w
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This project introduces an end-to-end framework for constructing integrated traffic network equilibrium models, which can serve as lightweight travel demand models, directly from multi-day aggregate traffic state observations. Unknown components on both the supply and demand sides are parameterized with computational graphs and embedded in a variat
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Aggregate materials used in the base and subbase layers of pavements provide structural support and drainability to Minnesota roads. But the supply of locally available high-quality aggregate material is becoming increasingly scarce. This project explored sustainable and cost-effective solutions for constructing durable flexible pavement roads with
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Concrete overlays for existing concrete and asphalt roads have been shown to be a viable rehabilitation or replacement option. This research project evaluated three unbonded concrete overlay (UBOL) projects in Illinois with high, medium, and very low truck volumes. The project’s goal was to assess each overlay’s performance including the influence
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Despite being prohibited from walking on freeways per federal laws, 14% to 17% of all pedestrian crashes in the United States happen on the interstates. Examining these crashes within the context of the safe systems approach is essential, with an emphasis on mitigating safety risks for all road users. This study investigates the correlates of pedes
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This report provides a comprehensive assessment and availability of the technical resources required in the development of a Central Building Information Modeling (BIM) Transportation Library (CBTL), outlining its foundational requirements based on past research, related projects, and stakeholder engagement. The CBTL is envisioned as a nationally a
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This report summarizes the 33rd United States–Japan Bridge Engineering Workshop, an event that convenes bridge engineers from both countries. The workshop serves as a platform to exchange innovative ideas and technologies, as well as to share crucial knowledge and lessons learned, all with the aim of advancing bridge engineering. The 33rd workshop
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The growing popularity of electric scooters (e-scooters) in urban environments has led to increased media coverage on their perceived danger both to the rider and to other users of the roadway. Media surrounding traffic collisions has long been criticized by safety researchers and activists for implicitly assigning blame to more vulnerable road use
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The researchers conducted a comprehensive literature review to evaluate the current state of practice surrounding crash rates and severity at midblock crossings. They examined technical reports and publications from transportation agencies, FHWA, NCHRP, and peer-reviewed journals. Findings were synthesized into a detailed summary of risk factors, p
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The research team conducted a thorough review of the state of the art and state of the practice of complete street pedestrian and bicycle safety countermeasures. They developed a thorough review of techniques used to compute crash modification factors for safety countermeasures, including signal operations strategies. They produced a discussion of
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The primary objectives of this research project were to (1) conduct an overview analysis of factors affecting unit prices, (2) identify factors affecting unit prices in Texas, (3) create a unit price estimation database, (4) create a spatio-temporal unit price estimation model considering the factors affecting unit prices, (5) develop a GIS-based v
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Students on university campuses have several available options for travel, including cars, buses, and micromobility, the latter of which encompasses bicycles and more recently, shared e-scooters (e-scooters). E-scooters are lightweight, electric vehicles which can be rented or purchased easily. They offer an ideal option to close the first/last-mil
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The goal of this project was to identify and update the tests and specifications in Item 300 as needed to ensure that the test methods and specifications are relevant, not redundant, and up-to-date. A review of most materials in Item 300 was in the scope of this project; however, crack sealers, asphalt-rubber binders, and recycling agents were not
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