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.
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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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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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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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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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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This Special Crash Investigations report documents the fatal rollover crash of a 2019 Chevrolet Equinox that moved into the lane of a 2016 Honda CR-V. The Chevrolet went out of control, rolled down a dirt embankment and rolled over. The Chevrolet driver was pronounced deceased on-scene, and the belted 52-year-old front passenger was hospitalized fo
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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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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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This project spanning the year 2025 set up 17 additional City intersections, raising the total locations reporting data to 19. Note that similar to the NDDOT sponsored pilot project, this phase of traffic data collection and reporting used existing infrastructure without the need to purchase or maintain any additional traffic data collection device
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This report covers analyses of Caltrans’ near-fault adjustment factors as recommended in the Caltrans Seismic Design Criteria. The report has two large chapters. Chapter 1 builds on prior the University of California Los Angeles studies that performed probabilistic seismic hazard analyses at numerous California sites across a range of return period
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Urban areas experience elevated pavement temperatures due to the urban heat island (UHI) effect, which increases cooling energy demand and associated carbon emissions. In this project, the work focused on three main components: (1) a comprehensive mechanical study of precast concrete mixes containing microencapsulated organic phase change material
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Elevated concentrations of air pollutants can have serious impacts on human health, the environment, and Colorado’s ecosystems. The Colorado Department of Transportation (CDOT) has prioritized protecting air quality in accordance with the Colorado Air Pollution Prevention and Control Act (Section 25-7-101 et seq., C.R.S., 2017). This research quant
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Effective drainage is critical for preserving pavement integrity and extending service life, yet network-level methods for evaluating pavement drainage conditions remain limited. This study presents a practical methodology for assessing pavement drainage conditions using data from the Louisiana Department of Transportation and Development’s (DOTD)
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This report presents a new framework for applying fines content corrections in soil liquefaction evaluations. Fines content affects both penetration resistance and cyclic resistance, but current methods use a single correction to represent both effects. This study separates these influences by using variable-rate CPT data to assess the effect of fi
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The primary purpose of this research was to develop and propose procedures for incorporating partnerships with utility stakeholders into the early stages of the project development process at the Iowa Department of Transportation (Iowa DOT), with the broader goal of streamlining workflows to reduce utility-related delays and cost overruns.
Nighttime work zones pose increased risks for both drivers and workers due to the challenge of ensuring adequate visibility while minimizing glare. Current lighting practices vary widely across public agencies, often resulting in excessive illumination and poor glare control. This study evaluated the performance of nighttime lighting systems throug
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This objectives of this project were as follows: •Investigate how the characteristics of lighting—specifically glare, luminance, and visibility—affect the visual performance of construction workers. •Examine the influence of lighting arrangements (i.e., the orientation and positioning of light towers) on the perceptions of both construction workers
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United States. Department of Transportation. National Highway Traffic Safety Administration. National Center for Statistics and Analysis
2025-12-01
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Traffic Safety Facts
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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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Chloride-based brine deicers are widely used to maintain winter roadway safety, but their performance drops in extreme cold as meltwater dilutes the brine, and their runoff accelerates concrete deterioration, rebar corrosion, and ecological harm. This report investigates sustainable, high-performance deicing formulations that enhance low-temperatur
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