The TRB National Cooperative Highway Research Program's NCHRP Synthesis 551: Highway Hydraulic Engineering State of Practice documents significant changes in highway hydraulic engineering practices implemented by state departments of transportation (DOTs) over the past decade. The synthesis focuses on eight subtopics of highway hydraulic engineering: roadway drainage; culvert aquatic organism passage; bridge scour computations and countermeasures; advanced hydraulic modeling; regulatory requirements; flo...

Performance testing of asphalt mixtures is becoming more widespread for a variety of reasons and with a variety of testing devices. The tests results are sensitive to the procedures used in preparation of the specimens. Guidelines exist for conducting the tests; however, they do not all provide uniform or comprehensive direction for fabricating test specimens. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 552: Practices for Fabricating Asphalt Specimens for Performance Testing i...

Collecting paper load delivery tickets at highway construction projects is an outdated practice that exposes construction inspectors to many safety hazards. State transportation agencies (STAs) have looked for decades toward automating this process through electronic ticketing, or e-ticketing. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 545: Electronic Ticketing of Materials for Construction Management examines the current state of practice of e-ticketing among STAs. Further, ...

Current legislation and subsequent asset management rules require state departments of transportation (DOTs) to conduct statewide evaluations of roads, highways, and bridges that have required repair and reconstruction activities two or more times since 1997 due to emergency events as declared by the president of the United States or by a state’s governor. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 556: Asset Management Approaches to Identifying and Evaluating Assets Damaged ...

Scaling loose rock from highway rock slopes is an important aspect of improving rock slope safety in mountainous areas, according to input from 42 state departments of transportation and two regional divisions of the Office of Federal Lands Highway. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 555: Estimating and Contracting Rock Slope Scaling Adjacent to Highways documents current rock slope scaling practices adjacent to highways. An appendices document is also included as par...

State departments of transportation often encounter public resistance to alternative intersections, with 86% of respondents in a new survey of state DOTs agreeing or strongly agreeing that public resistance hinders their implementation. Public resistance can vary among projects based on intersection type and whether the project was initiated at the local or state level. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 550: Alternative Intersection Design and Selection documents the...

Geophysical methods provide a means to rapidly and economically characterize subsurface conditions and infer soil properties over a spatial extent that is not possible with conventional methods. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 547: Advancements in Use of Geophysical Methods for Transportation Projects evaluates the current state of practice in the use of geophysical methods by state transportation agencies. Challenges and obstacles remain that must be overcome if r...

Sixty-eight percent of the states who responded to a survey indicated their agency has a documented process for as-built development. They said handwritten notes were the most commonly used method to capture as-built data (86%), followed by electronic notes (76%), and then photographs (33%). Some states use more than one option to capture as-built data. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 548: Development and Use of As-Built Plans by State Departments of Transportation...

Most U.S. state departments of transportation (DOTs) are collecting weigh-in-motion data with a wide variety of sensor types and using them in a variety of applications. Many agencies use WIM data to aid in pavement design, although most are not currently using a Pavement ME (mechanistic-empirical) Design application. WIM for bridge and asset management purposes is used much less often. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 546: Use of Weigh-in-Motion Data for Pavement, ...

Managing access connections to roadways is vital to safety and operational performance of roadways for all users. Given the separation of authority between state and local governments over land development and access, intergovernmental coordination is integral to effective access management. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 549: Incorporating Roadway Access Management into Local Ordinances documents regulatory tools and practices used by local governments to impleme...