Fhwa Publications

TRB's National Cooperative Highway Research Program (NCHRP) Report 672: Roundabouts: An Informational Guide - Second Edition explores the planning, design, construction, maintenance, and operation of roundabouts. The report also addresses issues that may be useful in helping to explain the trade-offs associated with roundabouts. This report updates the U.S. Federal Highway Administration's Roundabouts: An Informational Guide, based on experience gained in the United States since that guide was published in 2000.

This handbook, which was developed in recognition of the need for the compilation and dissemination of information on advanced traffic control systems, presents the basic principles for the planning, design, and implementation of such systems for urban streets and freeways. The presentation concept and organization of this handbook is developed from the viewpoint of systems engineering. Traffic control studies are described, and traffic control and surveillance concepts are reviewed. Hardware components are outlined, and computer concepts, and communication concepts are stated. Local and central controllers are described, as well as display, television and driver information systems. Available systems technology and candidate system definition, evaluation and implementation are also covered. The management of traffic control systems is discussed.

Intended to assist agencies responsible for incident management activities on public roadways to improve their programs and operations.Organized into three major sections: Introduction to incident management; organizing, planning, designing and implementing an incident management program; operational and technical approaches to improving the incident management process.

The first book to provide a detailed overview of Geosynthetic Reinforced Soil Walls Geosynthetic Reinforced Soil (GRS) Walls deploy horizontal layers of closely spaced tensile inclusion in the fill material to achieve stability of a soil mass. GRS walls are more adaptable to different environmental conditions, more economical, and offer high performance in a wide range of transportation infrastructure applications. This book addresses both GRS and GMSE, with a much stronger emphasis on the former. For completeness, it begins with a review of shear strength of soils and classical earth pressure theories. It then goes on to examine the use of geosynthetics as reinforcement, and followed by the load-deformation behavior of GRS mass as a soil-geosynthetic composite, reinforcing mechanisms of GRS, and GRS walls with different types of facing. Finally, the book finishes by covering design concepts with design examples for different loading and geometric conditions, and the construction of GRS walls, including typical construction procedures and general construction guidelines. The number of GRS walls and abutments built to date is relatively low due to lack of understanding of GRS. While failure rate of GMSE has been estimated to be around 5%, failure of GRS has been found to be practically nil, with studies suggesting many advantages, including a smaller susceptibility to long-term creep and stronger resistance to seismic loads when well-compacted granular fill is employed. Geosynthetic Reinforced Soil (GRS) Walls will serve as an excellent guide or reference for wall projects such as transportation infrastructure—including roadways, bridges, retaining walls, and earth slopes—that are in dire need of repair and replacement in the U.S. and abroad. Covers both GRS and GMSE (MSE with geosynthetics as reinforcement); with much greater emphasis on GRS walls Showcases reinforcing mechanisms, engineering behavior, and design concepts of GRS and includes many step-by-step design examples Features information on typical construction procedures and general construction guidelines Includes hundreds of line drawings and photos Geosynthetic Reinforced Soil (GRS) Walls is an important book for practicing geotechnical engineers and structural engineers, as well as for advanced students of civil, structural, and geotechnical engineering.