TRB's National Cooperative Highway Research Program (NCHRP)  Web-Only Document 247: Managing Geotechnical Risks in Design–Build Projects documents the research effort to produce NCHRP Research Report 884 : Guidelines for Managing Geotechnical Risks in Design–Build Projects. NCHRP Research Report 884 provides guidelines for the implementation of geotechnical risk management measures for design –build project delivery . The guidelines provide five strategies for aligning a transportation agency and it...

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 246: Volume 1: TRAQS User Guide provides guidance for using the TRansportation Air Quality System (TRAQS). TRAQS is an open source software designed to conduct mobile air quality assessments for three primary purposes: Project-Level Conformity (Hot-Spot Analyses) National Environmental Policy Act (NEPA) General Transportation Planning TRAQS is designed to streamline the model process and minimize any limitations of standalone s...

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 246: Volume 2: TRAQS: A Combined Interface for Project-Level Air Quality Analysis documents the development of TRAQS (TRansportation Air Quality System), a Graphical User Interface-based software application that simplifies project-level air quality analysis of mobile source emissions. TRAQS integrates the “modeling chain” components of traffic activity, mobile emissions, and air dispersion modeling. TRAQS is designed to stream...

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 255: Improved Analysis of Two-Lane Highway Capacity and Operational Performance supplements the sixth edition of the Highway Capacity Manual (HCM). Specifically, this project includes the following updates: the development of a more realistic speed-flow relationship the introduction of a new service measure—follower density a new headway threshold value to better identify follower status development of a percent-followers flow ...

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 230: Developing an Expanded Functional Classification System for More Flexibility in Geometric Design, which documents the methodology of 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, NCHRP Web-Only Document 230 provides additional contexts beyond urban and ...

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 251: Spot Painting to Extend Highway Bridge Coating Life: Volume 2: Research Overview documents the evaluation method for a guidance document that provides approaches for employing spot painting in a cost-effective, safe, and environmentally compliant manner. Bridge coatings are the primary means of corrosion protection for steel bridges in the United States. Most bridge coatings tend to fail prematurely in localized areas...

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 251: Spot Painting to Extend Highway Bridge Coating Life: Volume 1: Guidance provides approaches for employing spot painting in a cost-effective, safe, and environmentally compliant manner. Bridge coatings are the primary means of corrosion protection for steel bridges in the United States. Most bridge coatings tend to fail prematurely in localized areas and spot painting can be used restore the lost corrosion protection and ex...

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 250: Use of Automated Machine Guidance within the Transportation Industry studies automated machine guidance (AMG) implementation barriers and develop strategies for effective implementation of AMG technology in construction operations. AMG links design software with construction equipment to direct the operations of construction machinery with a high level of precision, and improve the speed and accuracy of the construction pr...

TRB's National Highway Cooperative Research Program (NCHRP) Web-Only Document 245: Bridge Superstructure Tolerance to Total and Differential Foundation Movements develops an understanding of the levels of support movements that bridges may tolerate before exceeding strength or service limit states. This research explores analytical procedures to objectively determine the acceptable levels of bridge foundation movements based upon superstructure tolerance considering American Association of State Highway ...

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 242: Recommended AASHTO Guide Specifications for ABC Design and Construction documents the results of a synthesis of past research regarding Accelerated Bridge Construction (ABC), leading to the development of Guide Specifications for Accelerated Bridge Construction. Part 1 of the report includes Design Specifications for ABC. Part 2 includes construction specifications. All current ABC technologies are covered in the specifica...