Search results
Results from the WOW.Com Content Network
In transportation engineering, the K factor is defined as the proportion of annual average daily traffic occurring in an hour. [1] This factor is used for designing and analyzing the flow of traffic on highways. K factors must be calculated at a continuous count station, usually an "automatic traffic recorder", for a year before being determined.
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 concept of design speed is evolving. 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 ...
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 American Association of State Highway and Transportation Officials (AASHTO) is a standards setting body which publishes specifications, test protocols, and guidelines that are used in highway design and construction throughout the United States. Despite its name, the association represents not only highways but air, rail, water, and public ...
In 1994, the AASHTO Green Book [1] defined the operating speed as "the highest overall speed at which a driver can travel on a given highway under favorable weather conditions and under prevailing traffic conditions without at any time exceeding the safe speed as determined by the design speed on a section-by-section basis," a definition which ...
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).
These units can be used to certify inertial profilers as a reference device since they have a sampling interval less than 2.75-inches per AASHTO PP49. [18] Dynamic measurements of the road profile are done with vehicle mounted instruments.