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.
Rumble strips are roadway safety countermeasures that alert inattentive drivers by generating in-vehicle noise to minimize roadway departure crashes and prompt speed reduction for vehicles approaching stop-controlled intersections. Despite these safety benefits, they often generate external noise and complaints from nearby residents. This report pr
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This study focused on improving light weight deflectometer (LWD) testing protocols and understanding material and equipment variability. The Indiana Department of Transportation (INDOT) adopted the LWD test for its efficiency and effectiveness in measuring soil stiffness, a crucial parameter for pavement structural layers. However, challenges remai
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The Massachusetts Department of Transportation (MassDOT) has sponsored multiple projects to implement the Mechanistic-Empirical Pavement Design Guide (MEPDG). Due to the complexity of this research, a four-phase approach spanning several years was proposed. This report focuses on Phase 3. In Phase 3, MassDOT concentrated on using the Long-Term Pave
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The objective of this project was to evaluate the expected impacts of truck automation and platooning on the Kansas workforce and formulate strategies to mitigate potential negative effects. The study was comprised of two phases: (1) a systematic literature review and (2) the compilation of insights from industry, workforce, and policymakers to cre
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The concept of automated freight transit began with platooning, which refers to one leading truck with a driver that controls two or three driverless, wirelessly connected trucks that follow at closely spaced gaps. Modern technology often displaces current jobs and required skills over time, but the potential for the high displacement of profession
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Minimizing pavement impact on wet weather crashes is essential to the Wet Surface Crash Reduction Program (WSCRP). Currently, the Texas Department of Transportation has two methods to evaluate pavement friction: the Safer by Design (SBD) method and the pavement surface aggregate classification selection, Form 2088. The research team developed a fra
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Supplemental cementitious materials (SCMs), such as fly ash, slag, silica fume, and metakaolin have become commonplace in Florida concrete, particularly for high durability or high-strength concrete. The Florida Department of Transportation (FDOT) currently allows fly ash to be used as a cement replacement at 18-50% levels and slag cement to be sub
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Traditionally, MoDOT performed bridge load ratings using the Load Factor Rating (LFR) methodology. With the adoption of Load and Resistance Factor Design based Load and Resistance Factor Rating (LRFR) methodology, MoDOT is migrating to LRFR for rating bridges. The primary goal of this study is to develop and recommend load posting policies using th
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The major objective of this study was to develop scientifically based recommendations for acceptable California Bearing Ratio (CBR) values for Kansas subgrades. To this end, multiple statistical analyses including: 1) Principal Component Regression Analysis (PCRA), 2) Regression Analysis (RA), 3) Multivariate Principal Component Regression Analysis
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The ability to accurately detect sulfates in an existing subgrade has been a major challenge for INDOT’s pavement maintenance and rehabilitation projects. Although naturally occurring sulfates in soil pose a significant construction challenge, detecting sulfates in an existing subgrade may be problematic and costly, given that the presence of sulfa
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The spacing of access points is one of the most critical elements in access management. This project aims to investigate the effect of access spacing on crash risk using scientifically rigorous statistical methods and to examine VDOT’s current access spacing standards. Specifically, the study focuses on unsignalized access types located on principa
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Automating the estimation of winter road surface conditions has the potential to improve the speed, efficiency, and cost-effectiveness of winter road maintenance activities.
California Bearing Ratio (CBR) of subgrade soils, which can be used in design of flexible pavements, can be obtained from Dynamic Cone Penetrometer (DCP) tests through a statistical correlation. The main objective of this study was to determine an acceptable CBR value based on the use of statistical pavement performance evaluation models. To this e
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A potential vulnerability of a tower drive vertical lift bridge is a failure to maintain level operation over the length or width of its movable span; this is known as longitudinal or transverse skew, respectively. When either of these conditions occurs, they can cause the movable span to jam in its guides; without adequate protection, this can lea
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The Bear Tracks Automated Shuttle Pilot was a research project that included the 12-month operation (August 2022-July 2023) of a Level 3 Automated Vehicle (AV) Shuttle along a 1.5-mile-long route in the city of White Bear Lake. The shuttle itself was a self-driving, electric, multi-passenger vehicle that drove at a speed between 10-12 miles per hou
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This research addresses the application of precast columns in Texas bridge construction. The project combines experimental and analytical methods to develop innovative design concepts and construction details for precast concrete columns. Key design concept includes a spun-cast precast shell filled with a cast-in-place (CIP) core and connecting rei
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The Variable Pedestrian Clearance Interval (VPCI) project consisted of deploying, testing, and analyzing the results of installing video at an intersection to extend the Flashing Don't Walk (FDW) interval as needed when pedestrians were still located within the crosswalk.
Reducing the number of through travel lanes requires drivers to decide where and when they will merge from the lane that is being dropped (the short lane) to the adjacent through lane. When a large proportion of drivers choose to merge significantly upstream, this can result in poor lane utilization at an upstream signal which, in turn, leads to un
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Traffic data are essential for decision-making by state departments of transportation in planning, designing, operating, maintaining, and rehabilitating transportation systems. However, collecting traffic counts at numerous portable sites in rural areas demands significant time and resources. In response, the Georgia Department of Transportation (G
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This study focused on improving light weight deflectometer (LWD) testing protocols and understanding material and equipment variability. The Indiana Department of Transportation (INDOT) adopted the LWD test for its efficiency and effectiveness in measuring soil stiffness, a crucial parameter for pavement structural layers. However, challenges remai
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