Over the last decade, state departments of transportation (DOTs) have begun to use vehicle probe and cellular GPS data for a variety of purposes, including real-time traffic and incident monitoring, highway condition, and travel demand management. DOTs are also using vehicle probe and cellular GPS data to inform system planning and investment decisions. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 561: Use of Vehicle Probe and Cellular GPS Data by State Departments of Transport...

Digital terrain models (DTMs) are three-dimensional (3D) models of the ground surface showing natural features such as ridges and breaklines. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 560: Practices for Construction-Ready Digital Terrain Models documents processes and strategies used by state departments of transportation (DOTs) for the use and transfer of DTMs from design into the construction phase of highway projects.

In March 2010, the U.S. Department of Transportation (DOT) released a policy statement supporting the development of fully integrated transportation networks. The policy is to “incorporate safe and convenient walking and bicycle facilities into transportation projects.” The TRB National Cooperative Highway Research Program's NCHRP Synthesis 558: Availability and Use of Pedestrian Infrastructure Data to Support Active Transportation Planning documents how state DOTs are collecting, managing, sharing, and ...

There is a wide disparity between the goals that state departments of transportation (DOTs) have for priced managed lanes and the public assumption for those goals. The public tends to be highly skeptical of priced managed lanes because the concept is difficult to explain to a nontechnical audience. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 559: Emerging Challenges to Priced Managed Lanes provides an overview of the state of the practice of how state DOTs address challenges ...

In 2017, the latest year for which data are available, 887 fatal utility pole crashes occurred in the United States, accounting for 914 fatalities. These numbers were about the same as those in recent years but lower than such fatality numbers from a decade or two ago. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 557: Utility Pole Safety and Hazard Evaluation Approaches summarizes the strategies, policies, and technologies that state transportation agencies (STAs) and utility o...

This classic 1978 report remains highly relevant, with today's frequent extreme weather, reviews measures taken by highway agencies to mitigate the impact of adverse weather conditions. Practices related to a number of specific construction activities are discussed. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 47: Effect of Weather on Highway Construction explores how materials, equipment, personnel, and the quality and quantity of work can be adversely affected by weather. De...

Geotechnical instrumentation and monitoring technologies have been used to inform safety, operational, and treatment decisions for unstable slopes. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 554: Advances in Unstable Slope Instrumentation and Monitoring documents and synthesizes the state of practice for implementation and use of advancements in unstable slope instrumentation and monitoring by state departments of transportation over approximately the last decade. The types o...

Pavement warranties have been common in the United States at various points in time, coming back into favor during the 1990s. While there is no national pavement warranty standard, agencies have developed their own specifications with varying criteria. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 553: Performance-Based Pavement Warranty Practices documents highway agency practices associated with the use of performance-based pavement warranties, focusing on asphalt, concrete, a...

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...