Available accident files are used to generate a 4l2-accident data base of guardrail impacts. This base is analyzed to develop a statistical model for predicting accident severity index (ASI) as a function of vehicle type or weight, impact speed, and impact angle. Reported full-scale test results are used to generate a 9l-test data base of guardrail
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In designing and locating pedestrian over and undercrossing structures, accessibility for handicapped persons is an important consideration. Features needed to provide accessibility should be incorporated into the structures unless it is shown that it is impractical to do so. Even when full accessibility is not provided, as many of the handicapped
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The great increase in highway construction beginning in the 1950's made evident the need for better control of materials .and construction. A comprehensive research and development program was begun to use statistical methods for quality assurance in highway construction. The effort since has resulted in quality control and acceptance plans which a
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The purpose of this research was to develop warrants for pedestrian over and underpasses or grade separated pedestrian crossings (GSPCs). Currently there are no established nationally acceptable warrants to serve as standards in deciding whether or not to build a GSPC. This research was conducted by first performing a literature review of existing
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This report describes the development of formulas which predict the severity of accidents at public rail-highway crossings. They employ the previously developed DOT accident prediction formula, U.S. DOT-AAR National Rail-Highway Crossing Inventory, and the FRA accident files. With these new formulas used in the DOT Resource Allocation Procedure, in
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The literature relating asphalt chemical composition and asphalt durability was reviewed and interpreted. Two major chemical factors affecting asphalt durability are (1) compatibility of the interacting asphalt components and (2) resistance to change from oxidative aging. Historically, studies of asphalt have been facilitated by separation of aspha
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Various capabilities of several versions of the VESYS flexible pavement model have been combined into a single computer program called VESYS IV-B. The resulting computer program was also edited and modularized to make it more convenient to use and to modify in the future. VESYS IV-B now models an n-layer flexible pavement structure using resilient
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The use of lime and lime-fly ash mixtures to increase the shear strength and to decrease the plasticity of clay soils is widely accepted. However, the difficulties involved with treating large quantities of in-situ soils or embankment soils in the traditional manner are also recognized. A relatively new technique for treating troublesome clays in p
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This study consisted of strength analyses of five in-service bridge railing systems, thirty full-scale vehicle crash tests on those railing systems and on a load measuring wall, the development of recommended design guidelines and development of recommended performance standards. The spectrum of vehicles addressed ranged from an 1,800 lb Honda seda
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Pavement damage functions were developed for both flexible and rigid pavement distresses that were considered significant as generators of major repair or rehabilitation. These damage functions were then used to develop load equivalence factors for each of these significant distresses. The result of this is a family of damage functions or distress
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The Combination Probe—A New Instrument for Subsurface Exploration; Driver Characteristics Impacting Highway Design and Operations; Foundation Engineering Research: Part 2—Pile Foundations; The UTCS Experience
This study consisted of strength analyses of five in-service bridge railingsystems, thirty full-scale vehicle crash tests on those railing systems andon a load measuring wall, the development of recommended design guidelines anddeve1opment of recommended performance standards.The spectrum of vehicles addressed ranged from an 1,800 lb Honda sedan to
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This study investigates steps that can be taken to reduce the risk, damage, and fatalities from fires in existing and future highway tunnels and the effect of unrestricted transit of hazardous materials through them. The history of highway tunnel fires is examined to discover the design and operating features bearing on ignition, spread, detection,
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This report summarizes the research undertaken to identify the sources of highway pollutants, and to determine their deposition and accumulation within the highway system and subsequent removal from the highway system to the surrounding environment. The purpose of this research was to identify opportunities to practice pollution mitigation. Researc
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The overall objectives of this research were to identify the sources of highway pollutants, and to determine their deposition and accumulation within the highway system and subsequent removal from the highway system to the surrounding environment. The purpose of this research was to identify opportunities to practice pollution mitigation. Data coll
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The overall objectives of this research were to identify the sources of highway pollutants, and to determine their deposition and accumulation within the highway system and subsequent removal from the highway system to the surrounding environment. The purpose of this research was to identify opportunities to practice pollution mitigation. Data coll
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This volume describes in summary form the research program conducted to evaluate the feasibility of conducting tests of model piles and pile groups using the geotechnical centrifuge. The goals of the program are described, the testing programs in both sand and clay are briefly discussed, important results are presented and conclusions and recommend
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