Current practices used by state departments of transporttion to design and manage the urban freeway roadsides (UFRs) environment is the focus of National Cooperative Highway Research Program (NCHRP) Synthesis 539: Landscape Development and Management Practices for Urban Freeway Roadsides. The urban freeway roadsides (UFRs) for this synthesis are those roadsides associated with high visibility urban freeways with limited pedestrian access, such as wider medians, interchanges, and overpasses. The UFR is pa...

The uses and levels of maturity of five advanced technology areas visualization and modeling, interconnected technologies, safety technologies, instrumentation and sensors, and unmanned aircraft systems in transportation highway construction projects are documented in TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 534: Emerging Technologies for Construction Delivery. The synthesis also investigates the implementation barriers and success factors for these technology areas and discu...

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 531 documents agency practices, challenges, and successes in conducting automated pavement condition surveys. The report also includes three case examples that provide additional information on agency practices for conducting automated pavement surveys. Pavement condition data is a critical component for pavement management systems in state departments of transportation (DOTs). The data is used to establish budget needs, support asset ...

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 533 identifies the current state of practice among state departments of transportation (DOTs) regarding selection and setup of very short duration work zone (VSDWZ). The report presents case examples of four state DOTs along with an in-depth analysis of the VSDWZ policies of these states. The case example agencies have developed specific guidance on the topic for their jurisdictions. VSDWZ activities are those activities not defined in...

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 538: Practices for Online Public Involvement summarizes current practices regarding online public participation strategies being used by state departments of transportation (DOTs), as well as explores the effectiveness of using these strategies and tools. Online public participation methods offer agencies the potential for expanded participation and also present new challenges and demand new thinking about the appropriate mix of techni...

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 537: Impact of Asphalt Thickness on Pavement Quality documents transportation agency policy for lift thickness and minimum compaction requirements on resultant asphalt pavement quality. To achieve expected pavement performance, it is important that asphalt concrete (AC) have adequate density. A critical factor in achieving this density is the ratio of lift thickness to nominal maximum aggregate size (t/NMAS). The information in the rep...

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 532: Seismic Design of Non-Conventional Bridges documents seismic design approaches and criteria used for “non-conventional” bridges, such as long-span cable-supported bridges, bridges with truss tower substructures, and arch bridges. Design of conventional bridges for seismic demands in the United States is based on one of two American Association of State Highway Transportation Officials (AASHTO) documents: the AASHTO Load and Resist...

TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 536: Bridge Demolition Practices documents practices used by bridge owners to manage and administer bridge demolition in construction projects. Each year hundreds of bridges are rebuilt or are entirely replaced as part of highway construction projects. Bridge reconstruction or replacement work often entails demolition of part or all of the bridge structure. Unintended events resulting in injury, project delays, and traffic disruptions ...

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 522: Managing State Transportation Research Programs identifies the current state of practice of managing state transportation research programs. The report highlights existing resources, desired individual skill sets, core competencies, and structures that are in place for departments of transportation (DOTs) to manage and conduct transportation research, especially federally funded research. In essence, NCHRP Synthesis 522 addresses ...

TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 528: Analyzing Data for Measuring Transportation Performance by State DOTs and MPOs summarizes what data state departments of transportation (DOTs) and metropolitan planning organizations (MPOs) are using and how they are measuring transportation performance. Knowledge about transportation data already exists, but may be fragmented, scattered, and unevaluated. This report synthesizes current knowledge and practice about data manag...