Transportation Research E-Circular 237: Innovations in Asphalt Mixture Design Procedures explores the fundamentals of asphalt mix design for improved durability and performance. Based off of presentations made at TRB's 95th Annual Meeting, the document examines presentations that cover ways to incorporate more binder into the mix with trials that modify the air void and void in mineral aggregate (VMA) requirements that complement the Superpave system. Performance testing ties together these approaches th...

TRB E-Circular 236: National Academies–TRB Forum on Preparing for Automated Vehicles and Shared Mobility summarizes the deliberations of a TRB forum launched in early 2018 to facilitate evidence-based research needed to deploy automated vehicle technologies in a manner and timeframe that informs policy to meet long-term goals. The deployments of automated vehicles, shared mobility services, and other transformational transportation technologies have the potential to dramatically increase safety, reduce c...

TRB's E-Circular 235: Glossary of Transportation Construction Quality Assurance Terms: Seventh Edition contains common terms and accepted practice in transportation construction quality assurance terminology. Transportation construction quality assurance (QA), like many other specialized subject areas, has its own unique language containing numerous technical terms or expressions having very specific meanings. Some of these terms are not well understood, and their use is subject to a variety of different...

TRB's E-Circular 234: Relationships of Laboratory Mixture Aging to Asphalt Mixture Performance summarizes the results from TRB Session 462: Relationship of Laboratory Mix Aging to Asphalt Mixture Performance, which was held during the 2016 TRB Annual Meeting. This circular includes four papers on addressing laboratory mix aging and explore handling asphalt mixtures at a production facility, varying the lab mix conditioning, and capturing situations found in the field.

TRB's E-Circular 233: Applying Census Data for Transportation explores a conference held on November 14-16, 2017, in Kansas City, Missouri that focused on the use of census data for transportation applications. The conference provided a forum for participants to share experiences with the use of Census data, including new techniques for integrating different data sets for use in transportation planning and decision making. The conference further provided an opportunity for participants to discuss opportu...

TRB's E-Circular 232: Automated Vehicle Symposium 2017: Summary of a Symposium highlights the themes from an event that took place on July 11–13, 2017 in San Francisco, California. The event explored the development, testing, building, and deployment of autonomous vehicles (AVs). The 2017 AVS provided the opportunity for communication, collaboration, and information sharing on a wide range of topics, including potential public policy, safety and security, ethical, and equity concerns, as well as technolo...

TRB's E-Circular 231: U.S. Department of Transportation’s Mobility on Demand Initiative summarizes the sessions and discussions of a workshop held on January 7, 2018 co-hosted by TRB and the U.S. Department of Transportation. The concept of Mobility on Demand (MOD) includes the ability for transportation providers to manage mobility rather than traffic through demand-responsive service, shifting use to alternate modes. MOD provides consumers with the ability to reserve, dispatch, or use services like rid...

TRB's E-Circular 230: Culverts and Soil–Structure Interaction: Fifty Years of Change and a Twenty-Year Projection summarizes the presentations from the TRB 93rd Annual Meeting on January 14, 2014 in Washington, D.C. In the past 40 to 50 years have seen significant changes in the pipe industry in terms of materials used, structure sizes, shapes, and joint capabilities. Design methodologies have become far more sophisticated, primarily through the use of load resistance factor design (LRFD) and comput...

TRB's E-Circular 229: 10th SHRP 2 Safety Data Symposium: From Analysis to Results explores the October 6, 2017 symposium that served as a forum for the exchange of ideas about uses and methods for the SHRP 2 Safety Data Program and identified lessons learned from working with the data. This symposium focused on safety data analysis, results, and applications to help researchers and practitioners learn more about safety data applications.

TRB's E-Circular 228: Rebuilding and Retrofitting the Transportation Infrastructure documents the presentations from a conference of the same name held in Washington, D.C., in September 2017. This meeting was the 11th in a series of Spotlight Conferences funded by the U.S. Department of Transportation’s (DOT) Office of the Assistant Secretary for Research and Technology, University Transportation Centers (UTC) Program. This event provided an opportunity to share ideas and needs about transportation infra...