Horizontal curves, comprising only about five percent of highway miles, account for a disproportionately high number of fatal crashes, nearly 25 percent. Excessive driving speed on curves is the leading cause of these run-off-road crashes, due to vehicles exceeding the amount of friction available. Understanding existing curve safety conditions, such as advisory speeds, is crucial for planning and designing safety countermeasures. The TRB IDEA (Innovations Deserving Exploratory Analysis) Program's NCHRP ...

As the airport industry continues to evolve to meet the latest workforce, operations, and technological developments, ensuring that small airports have the resources and information necessary to adapt is essential. The TRB Airport Cooperative Research Program's Impacts on Practice: Onboarding New Staff with ACRP Resources details how the Indiana Department of Transportation shares ACRP research products with new airport managers to provide guidance and real-world case studies for addressing a range of ai...

Access Management is defined as “the coordinated planning, regulation, and design of access between roadways and land development.” Transportation Research Circular E-C301: Access Management Safety and Design from the Curb to the Interchange for All Users contains extended abstracts from selected presentations presented at the Transportation Research Board 4th International/13th National Conference on Access Management, held June 24-26, 2024, in Boston, MA.

Dynamic modulus (E*) values significantly influence the estimates of pavement performance and life, and they are a key input for pavement design programs. Therefore, quick and accurate determination of E* values of asphalt mixtures is crucial for designing long-lasting pavements, saving taxpayers money, reducing emissions, and reducing traffic delays. The TRB IDEA (Innovations Deserving Exploratory Analysis) Program's NCHRP IDEA Final Report for Project 242: Development of an AI-Powered Dynamic Modulus T...

Transportation Research Circular E-C302: 2nd Conference on Advancing Transportation Equity , from the Transportation Research Board, summarizes the presentations and discussions from this event held July 15–18, 2024, in Baltimore, Maryland.

Simulation has become a crucial tool for evaluating the effectiveness of proposed capital investments aimed at improving transportation system performance. Factors such as persistent congestion, complex facility operations, and the rapid advancement of technologies and transportation systems management strategies have required agencies to invest in developing and utilizing simulation models. TR Circular E-C298: Transportation Systems Simulation Compendium , from the Transportation Research Board, provide...

U.S. airports that receive assistance from the federal government are required to comply with a number of obligations imposed by federal law. The TRB Airport Cooperative Research Program’s ACRP Legal Research Digest 21: Compilation of DOT and FAA Airport Legal Determinations and Opinion Letters as of December 31, 2023 covers legal matters that include the reasonableness of contractual terms, leasing practices, airport rules and regulations, airport charges imposed on aeronautical users, including airline...

Current state of practice methods to determine mixing and compaction temperatures for asphalt mixtures fail to reasonably explain the mixture workability mechanism and do not consider other important properties of asphalt mix such as aggregate properties and mix gradation. The TRB IDEA (Innovations Deserving Exploratory Analysis) Program's NCHRP IDEA Final Report for Project 246: Develop a Method for Selecting Low-Energy Mixing and Compaction Temperatures for Asphalt Mixtures Considering Asphalt Lubricat...

Retroreflectivity plays a crucial role in pavement markings as it enhances nighttime visibility for drivers. Yet, due to budget constraints, many state U.S agencies rarely monitor the retroreflectivity of their markings, and instead, restripe their markings based on visual inspection or fixed schedule. The TRB IDEA (Innovations Deserving Exploratory Analysis) Program's NCHRP IDEA Final Report for Project 237: New Tool for Predicting the Retroreflectivity (RL) of Pavement Markings details the development ...

Asphalt mix design has always been considered a balance of rutting resistance and durability. The conventional Superpave mix design system targets 4% air voids during design and is referred to in this circular as Superpave4. The Superpave5 concept is a modification to the conventional Superpave4 approach. Transportation Research Circular E-C300: Superpave5: How Increasing Air Voids Can Improve Asphalt Pavement Durability , from the Transportation Research Board, captures information exchanged during the ...