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AASHTO LRFD Bridge Design Specifications. This manual is the base bridge design manual that all DOTs use across the US. Manual for Assessing Safety Hardware (MASH), crash testing criteria for safety hardware devices for use on highways; it updates and replaces NCHRP Report 350. In addition to its publications, AASHTO performs or cooperates in ...
The following section pertains to only North American highway LOS standards as in the Highway Capacity Manual (HCM) and AASHTO Geometric Design of Highways and Streets ("Green Book"), using letters A through F, with A being the best and F being the worst, similar to academic grading. A: free flow. Traffic flows at or above the posted speed ...
The primary US guidance is found in A Policy on Geometric Design of Highways and Streets published by the American Association of State Highway and Transportation Officials (AASHTO). [2] Other standards include the Australian Guide to Road Design Archived 2011-11-09 at the Wayback Machine, and the British Design Manual for Roads.
The first edition of the Highway Capacity Manual was released in 1950 and contained 147 pages broken apart into eight parts. It was the result of a collaborative effort between the Transportation Research Board (TRB) and the Bureau of Public Roads, the predecessor to the Federal Highway Administration. [1]
American Association of State Highway and Transportation Officials: ... Page:AASHTO USRN 1976-07-13.pdf/5; Page:AASHTO USRN 1976-07-13.pdf/6; Usage on www.wikidata.org
Recovery areas: There should be no fixed objects in the clear zone, the width of which should be determined by the design speed in accordance with the current edition of AASHTO's Roadside Design Guide. When this is not possible, breakaway supports or barriers guarding the objects should be used. Special care should be taken in depressed ...
The present serviceability index (PSI) is a pavement performance measure.Introduced by the American Association of State Highway and Transportation Officials (AASHTO), the PSI is one of the most widely used pavement performance indicators after pavement condition index (PCI) and international roughness index (IRI).
The definition in the 1994 edition of the AASHTO Green Book, [10] was "the maximum safe speed that can be maintained over a specified section of highway when conditions are so favorable that the design features of the highway govern. The assumed design speed should be a logical one with respect to the topography, the adjacent land use, and the ...