The objective of this research project was to identify conspicuity, recognizability, and comprehensibility problems with object markers, particularly as they relate to the needs and capabilities of the older driver. This was accomplished through a series of tasks and three sets of experiments (problem identification, laboratory and field studies) w
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A combination concrete parapet and metal railing for performance level one of the 1989 AASHTO Guide Specifications for Bridge Railings was designed and tested while mounted both on a sidewalk and flush on the deck. The upper portion of the railing permits some visibility through the railing while the 42-in. (1.07-m) height is provided for pedestria
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Superpave is an acronym for Superior Performing Asphalt Pavements. Superpave is a new, comprehensive asphalt mix design and analysis system, a product of the Strategic Highway Research Program. Congress established SHRP in 1987 as a five-year, $150 million research program to improve the performance and durability of United States roads and to make
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The aging of our highway infrastructure has been accompanied by the realization that various preservation and enhancement activities will be increasingly commonplace well into the future. Because these activities must be carried out despite the presence of vehicular traffic, efforts are necessary to minimize the effect on traffic and roadway safety
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This document provides guidelines for the selection and design of appropriate countermeasures to mitigate potential damage to bridges and other highway components at stream crossings. A countermeasure matrix is presented as an aid to identify most types of countermeasures which have been used by State highway agencies (SHAs) for bridge scour and st
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The SPS-3 and SPS-4 experiments were constructed in 1990 under the Strategic Highway Research Program (SHRP) to evaluate the effectiveness of and to determine the optimum timing for applying preventive maintenance treatments for flexible and rigid pavements. Documentation of conclusions from recent field reviews to evaluate the performance of the m
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The research objectives were to determine performance criteria for acceptable pedestrian signal visibility and to study the comprehension of innovative and standard pedestrian signals. Two field studies and a video questionnaire were designed and implemented to test the visibility and comprehension of pedestrian signals. The rationale of these stud
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National statistics indicate that fatality rates on rural Federal-aid primary highways have been significantly higher compared to those for urban and rural Interstate highways and urban primary highways. Although this group of highways includes two-lane rural roads, an important component of the rural Federal-aid primary highways are multilane rura
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Retroreflective traffic control devices are designed to help offset the lack of visual cues in the nighttime driving environment. Currently, the Manual on Uniform Traffic Control Devices requires that signs be retroreflectorized, but no minimum in-service values are given for the level of retroreflectivity. Due to the degradation of retroreflective
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Shared resource projects are public-private arrangements that involve sharing public property such as rights-of-way and private resources such as telecommunications capacity and expertise. Typically, private telecommunications providers are granted access to public property for their own telecommunications infrastructure in exchange for providing i
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The following summary of the Federal Highway Administration bridge and structures related research program is provided for your general use and information. The goal of the research program is to develop a range of technologies to not only preserve and maintain our nation's bridges and structures, but to advance and develop new materials, new inspe
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On March 1, 1996, the U.S. Department of Transportation (US DOT) Grade Crossing Safety Task Force delivered a report entitled Accidents That Shouldn't Happen to Transportation Secretary Federico Pena. Secretary Pena had directed that the Task Force be convened to address factors that might have contributed to a fatal collision involving a commuter
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It is well known that during construction of any highway pavement, variations in layer material quality, environmental influences, homogeneity, and variations in construction technique all lead to nonuniform spatial variations in the layer material properties/layer thicknesses comprising the pavement structure. As vehicle loads are applied to the p
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This project was performed to develop guidelines for changes in the geometric design and operations at intersections with the greatest potential to aid in their use by older drivers and pedestrians. A literature review identified age-related diminished capabilities that affect performance at intersections, and examined current design standards and
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The 32-in. (813-mm) F-shape concrete parapet is similar to the New Jersey safety shape. The F-shape was designed and tested to performance level two of the 1989 AASHTO Guide Specifications for Bridge Railings and acceptable performance was obtained. Computed ultimate strength of the railing with the steel reinforcement used was 59 kips (263 kN).
A 42-in. (1.07-m) high F-shape concrete parapet bridge railing was designed and tested to performance level three of the 1989 AASHTO Guide Specifications for Bridge Railings. The parapet has a thickened section along the top to stiffen the top edge and enhance longitudinal distribution of the load. It was mounted on a 10-in. (254-mm) simulated brid
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A transition for the Oregon side-mounted thrie-beam bridge railing was developed and tested to performance level one of the 1989 AASHTO Guide Specifications for Bridge Railings. Acceptable performance of the transition was demonstrated. Post spacing in the transition area is 3 ft 1 1/2 in. (953 mm). A 12 ft 6 in. (3.81 m) length of thrie-beam which
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In some connections of W-beam and thrie-team guardrail elements, it is necessary to bolt together three thicknesses of rail element. Such a connection can not be assembled without enlarging the standard round connection bolt holes. One solution to this problem is to use elongated holes with the long axis of the hole at an angle to the longitudinal
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