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.
This report describes an investigation focused on characterizing the phenomenon of constraint-induced fracture (CIF) in steel bridges, specifically considering three classes of details which prior research has not adequately addressed: thick bearing stiffeners, connection plates, and orthogonal stiffeners with varying constraint-relief gap dimensio
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The Alabama Department of Transportation (ALDOT) employs infiltration swales, linear vegetated channels with engineered soil media, as a green infrastructure stormwater control measure along roadsides to reduce runoff discharge. This study evaluated the performance of infiltration swales and their media through laboratory experiments, field testing
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MDOT has been using the Distress Index (DI) since the inception of its pavement management system (PMS) in the early 1990s. DI was developed to help MDOT engineers decide, allocate budgets, and prioritize future maintenance or reconstruction activities. However, the raw data requirements for the DI are complicated (and somewhat unique compared to t
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This project was undertaken to support the Michigan Department of Transportation’s (MDOT) implementation of a new Pavement Management Tool (PMT), a decision-support system designed to optimize pavement project selection. The goal was to develop data-driven inputs for the PMT using MDOT’s extensive historical pavement condition and maintenance data,
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Evaluation of the design methods involved a comparison of results calculated from the popular design methods BS 8006-1, EBGEO, CUR226, and the Federal Highway Administration (FHWA) for three key design parameters (load efficacy, differential settlement and reinforcement strain). The measured data were available in the literature, including 24 full-
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This report provides comprehensive guidance for planning, locating, designing, and evaluating passing lanes on Kansas rural two-lane highways. It describes the role of passing in improving mobility by reducing platooning, lowering percent time spent following, and increasing travel speeds. Multiple passing lane configurations are outlined, with gui
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Full depth reclamation (FDR) using emulsified asphalt or foamed asphalt continues to grow in usage throughout Texas. These mixtures typically use a cement additive in the mix design. The cement additive reportedly contributes to early strength gain, which can be particularly important for projects that require daily opening to heavy traffic. Howeve
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A growing number of U.S. transit agencies are adding transit ambassadors to their systems to improve the customer service and safety experience for passengers. These personnel can play a variety of different roles, including providing wayfinding, system navigation, fare payment support, and other passenger support roles that enhance the customer ex
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Although visual inspections remain the primary method for bridge deck evaluation, they fail to detect hidden deterioration. Rapid-scanning nondestructive evaluation (NDE) techniques are gaining popularity, but their reliability compared with traditional methods is unclear. This study aimed to determine the reliability of multiple NDE methods for de
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This study presents a computational tool for predicting pavement performance using long-term temperature data from thermocouple trees embedded in three flexible and two rigid pavement sections at the MnROAD facility. The research leverages spectral and probabilistic analyses to assess thermal behavior and its impact on pavement condition. Temperatu
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This report presents a complete evaluation of the machine-vision-based dynamic retroreflectometer system (DRS) with a 30-m geometry scaled to 12-m, manufactured by Reflective Measurement Systems Ltd, 100% owners of RetroTekUSA. The assessment includes pavement marking evaluation, including line striping retroreflectivity, line striping width, color
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Traffic control devices are a primary means of communicating highway information to road users and play a key role in highway automation. The design, application, and maintenance of traffic control devices are under constant transformation as new technologies, methodologies, and policies are introduced. In addition, vehicle technologies and the roa
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The Bismarck-Mandan Regional Intelligent Transportation Systems (ITS) Architecture was developed under the guidance of the Bismarck-Mandan Metropolitan Planning Organization (Bis-Man MPO). Initially created in 2005, this architecture has undergone four updates in 2008, 2013, 2021, and 2025. Its primary purpose is to guide the implementation of ITS
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Rigid inclusions (RIs) have increasingly been used in ground improvement technology in the United States because they effectively reduce settlement, increase bearing capacity, and enhance stability. Several design methods have been developed to analyze RI-supported embankments based on various assumptions for transportation applications. This study
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This report provides comprehensive guidance for planning, locating, designing, and evaluating passing lanes on Kansas rural two-lane highways. It describes the role of passing in improving mobility by reducing platooning, lowering percent time spent following, and increasing travel speeds. Multiple passing lane configurations are outlined, with gui
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United States. Department of Transportation. National Highway Traffic Safety Administration
2025-12-01
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In 2024 NHTSA increased data collection sites from 32 to 40 for the 2024 Crash Investigation Sampling System (CISS). It also expanded the scope of data collection and investigated crashes involving nonmotorists. The 2024 CISS shows an estimated 2,879,549 police-reported motor vehicle crashes nationwide, representing the CISS target population of cr
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United States. Department of Transportation. National Highway Traffic Safety Administration
2025-12-01
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In 2024 NHTSA began upgrading the Crash Investigation Sampling System (CISS) with provisions in the Infrastructure Investment and Jobs Act (IIJA), which said “to enhance the collection of crash data by upgrading the [CISS] to include – 1) additional data collection sites; 2) an expanded scope that includes all crash types; and 3) on-scene investiga
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This study investigated the mechanical strength and freeze-thaw durability of carbonate-based aggregate quarry by-products (QBs) stabilized with cement alone and in combination with calcined clay (metakaolin, MK) for potential use in pavement foundation layers. The primary objective was to evaluate the chemical and physical characteristics of dolom
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This Special Crash Investigations report documents the on-site investigation of the rollover crash of a 2019 Subaru Outback Limited in North Carolina in November 2022 driven by a belted 34-year-old female with a belted 70-year-old female front passenger. The Subaru crossed into the oncoming lane, traveling more than half a mile before veering off t
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