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The measurement of IRI is required for data provided to the United States Federal Highway Administration, [1] [9] and is covered in several standards from ASTM International: ASTM E1926 - 08, [10] ASTM E1364 - 95(2005), [11] and others. IRI is also used to evaluate new pavement construction, to determine penalties or bonus payments based on ...
Long-Term Pavement Performance Program, known as LTPP, is a research project supported by Federal Highway Administration (FHWA) to collect and analyze pavement data in the United States and Canada. Currently, the LTPP acquires the largest road performance database.
A smoothness index for the road can be derived from a standard deviation analysis of the results. [4] As an example of a unit the Road Research Laboratory rolling straight-edge measures 3 metres (9.8 ft) in length with the sensor mounted at the midpoint. The unit was mounted on forty 127-millimetre (5.0 in) diameter road wheels mounted in pairs ...
The pavement condition index (PCI) is a numerical index between 0 and 100, which is used to indicate the general condition of a pavement section.The PCI is widely used in transportation civil engineering [1] and asset management, and many municipalities use it to measure the performance of their road infrastructure and their levels of service. [2]
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 ...
High-visibility vests tend to be standard equipment for highway construction workers and other people who work around roadways for a reason — they help drivers spot (and avoid hitting) the folks ...
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 ...
FWD data is most often used to calculate stiffness-related parameters of a pavement structure. The process of calculating the elastic moduli of individual layers in a multi-layer system (e.g. asphalt concrete on top of a base course on top of the subgrade) based on surface deflections is known as "backcalculation", as there is no closed-form solution.