TRB's National Cooperative Highway Research Program (NCHRP) Research Report 882: How Weather Affects the Noise You Hear from Highways documents the meteorological effects on roadway noise propagation under different atmospheric conditions. Highway noise changes from day to day and hour to hour—not just because of variations in traffic volumes, vehicle mix, and speed, but also because of the weather. The report develops guidance to identify when atmospheric conditions should or should not be considered in...

TRB's National Cooperative Highway Research Program (NCHRP) has released a pre-publication, non-edited version of Research Report 876: Guidelines for Integrating Safety and Cost-Effectiveness into Resurfacing, Restoration, and Rehabilitation (3R) Projects. The report presents an approach for estimating the cost-effectiveness of including safety and operational improvements in a resurfacing, restoration, or rehabilitation (3R) project. The approach uses the performance of the existing road in estimating t...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 879: Optimal Replacement Cycles of Highway Operations Equipment acts as a handbook on equipment replacement concepts and an instruction manual for making cost-effective replacement decisions. The research report presents a process for determining replacement needs for highway operations equipment, identifying candidate equipment units for replacement, and preparing an annual equipment replacement program. The products include a g...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 868: Cell Phone Location Data for Travel Behavior Analysis presents guidelines for transportation planners and travel modelers on how to evaluate the extent to which cell phone location data and associated products accurately depict travel. The report identifies whether and how these extensive data resources can be used to improve understanding of travel characteristics and the ability to model travel patterns and behavior more e...

TRB's National Cooperative Highway Research Program (NCHRP) has released a pre-publication, non-edited version of Research Report 890: Using Recycled Asphalt Shingles with Warm Mix Asphalt Technologies.  The report documents the development of a design and evaluation procedure that provides acceptable performance of asphalt mixtures incorporating warm mix asphalt (WMA) technologies and recycled asphalt shingles (RAS)—with and without recycled asphalt pavement (RAP)—for project-specific service condi...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 855: An Expanded Functional Classification System for Highways and Streets builds upon preliminary engineering of a design project, including developing the purpose and need. In particular, it provides additional contexts beyond urban and rural, facilitates accommodation of modes other than personal vehicles and adds overlays for transit and freight. Two case studies illustrating an application of the expanded system to actual pr...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 877: Performance-Based Mix Design for Porous Friction Courses presents a proposed mix design method for porous asphalt friction course (PFCs). PFCs have been used in the United States for many years. Their open aggregate gradations and resultant high air void contents provide PFCs with the ability to quickly remove water from the surface of a roadway, thus reducing the potential for vehicles to hydroplane and improving skid resis...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 873: Guidebook to Funding Transportation Through Land Value Return and Recycling presents guidance on ways to mobilize some portion of property-value increases to fund maintenance and operations as well as investment in the infrastructure. Because local government typically has authority to deal with matters related to land use and land-related revenue-generating mechanisms, access to land value return and recycling—a subset of r...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 872: Contribution of Steel Casing to Single Shaft Foundation Structural Resistance proposes revisions to bridge design specifications based on comprehensive analytical and testing programs for investigating the effects of steel casing. Bridges are often constructed with a single enlarged shaft foundation supporting a column. In many cases, the shaft foundation is constructed with a permanent steel casing. The combination of the s...

TRB's National Cooperative Highway Research Program (NCHRP) Research Report 874: The Transportation Research Thesaurus: Capabilities and Enhancements documents the results of a comprehensive assessment of the Transportation Research Thesaurus’s (TRT’s) capabilities and strategies for the TRT’s future development. The TRT is a structured, controlled vocabulary of terms in English, used by TRB and a variety of other organizations to support indexing, search, and retrieval of technical reports, research doc...