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Amjadi R.,TFHRC | Eccles K.,VHB Inc.
Public Roads | Year: 2011

The Federal Highway Administration (FHWA) and States in the US have collaborated to conduct research in order to improve safety at curves, where crash fatality rates remain comparatively high. The Connecticut Department of Transportation (ConnDOT) used fluorescent yellow sheeting to improve signing at horizontal curves. This included installing new signs or replacing existing ones. ConnDOT identified candidate locations for treatment through a regular safety program called the Suggested List of Surveillance Study Sites. The list uses crash data, traffic volumes, and roadway characteristics to identify intersections and road segments with higher than expected crash rates. TFHRC conducted an economic analysis to determine the relative cost effectiveness of curve delineation improvements. Some previous evaluations during this pooled fund study were retrospective, in that they looked at strategies that had been in place for years. The Kansas Department of Transportation (KDOT) is in the process of selecting curve sites for its part in the pooled fund study. Source


Arnold T.,TFHRC
Public Roads | Year: 2012

The focus of the Pavement Materials Team in the Federal Highway Administration's (FHWA) Office of Infrastructure Research & Development is to evaluate pavement and materials to optimize their use, extend pavement life, and reduce costs. A chemistry laboratory has existed within the Federal highway system for more than 100 years. Prevost Hubbard was chief of the Physical and Chemical Labs, Bureau of Public Roads, US Department of Agriculture from 1905-1919. The laboratory moved to its present location in 1950. Paving and bridge engineers concern themselves mostly with the bulk physical properties of materials. Yet, steel and concrete, like everything else, are composed of atoms and molecules. FHWA researchers at the TFHRC chemistry lab have an array of rapid spectroscopic, optical, and analytical tools at their disposal that enable them to study pavement materials at the atomic and molecular levels. Source


Amjadi R.,s Turner Fairbank Highway Research Center | Merritt D.,Transtec Group | Sherwood J.,TFHRC
Public Roads | Year: 2014

The Federal Highway Administration (FHWA) and 17 States collaborated to determine how to increase pavement friction through low- or no-cost surface treatments. The study titled, Evaluations of Low-Cost Safety Improvements Pooled Fund Study, Phase VI, researched on using crash data to measure the safety performance of pavement treatments. The researchers developed crash modification factors and benefit-to-cost ratios for nine pavement treatments, such as thin hot-mix asphalt overlays and diamond grinding, to examine their potential in reducing the frequency and severity of lane departure crashes. The pavement treatments considered in the final analysis included thin hot-mix asphalt (HMA) overlay. For the high friction surface treatment (HFST) sites, the researchers employed two analysis methodologies, the before-after method and the comparison-group method. The result of the study showed that the properties of pavement treatments change over time. Traffic and weather play a significant role in wearing down the surfaces, generally leading to a reduction in pavement texture and friction. Source


Duwadi S.R.,TFHRC | Munley E.,TFHRC
Public Roads | Year: 2011

The Federal Highway Administration (FHWA) has invested extensive research dollars into providing safer highway infrastructure to protect against earthquakes, floods, hurricanes, traffic and construction incidents, and structural collapses. Although there are only a handful of different bridge types, each structure is designed to fit its specific location and circumstances. That means each has its own distinct vulnerabilities, depending on the design type, location, and materials used to construct it. Understanding these vulnerabilities is key to finding workable solutions for protection. Transportation and security agencies further do not want counterterrorism strategies publicized, therefore development and deployment are seldom discussed openly, making sharing of information another challenge. Today, the US Department of Homeland Security (DHS) plays a critical role in this collaboration, stemming from its primary responsibility for ensuring the Nation's safety and security. In addition, the Transportation Research Board (TRB) had been addressing security issues prior to 9/11 and substantially expanded its effort after. Source

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