1,287 research outputs found

    Accident Analysis of Ice Control Operations

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    Highway maintenance involves all work necessary to assure that the highway system is kept safe, open to traffic, and in proper working order. During winter, the removal of snow and ice from streets, roads, and highways is a major maintenance operation. With more than 135 million motor vehicles registered in the United States and roughly four million miles of roads and streets, local governments must be prepared to deal with the removal of snow and ice to insure public safety, and to reduce the adverse impact on the affected area’s economy. Snow and ice covered roads can paralyze the functioning of the community and pose a considerable threat to the public safety. They produce hazardous driving conditions which increase traffic deaths, injuries, and property damage. The general assumption has always been that snow and ice on highways causes accidents. There are a number of reasons for this assumption. Snow and ice reduce the coefficient of friction between the pavement and vehicle tires, making maneuvering of the vehicle very difficult and occasionally impossible. Ice is not always apparent to the motorist and is not uniform, so that the driver is not always prepared when he encounters an icy section on the roadway. Vehicle mobility is reduced, causing possible severe disruption of important public emergency services, such as fire, police, and ambulance operations. Without close attention to the effective removal of snow and ice from roads, the economy of the region involved will suffer, and traffic accidents will escalate. Most activities of individuals, industries, utilities, schools, and government activities are handicapped in social and economic ways during the duration of snow and ice conditions on roads and streets

    Public Perceptions of the Midwest’s Pavements: Policies and Tradeoffs in Pavement Improvement

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    With the budget crisis plaguing so many states, pavement management will compete more vigorously for limited funds. Findings reported from a tri-state pooled-fund research project provide insights and guidelines for pavement improvement derived from the perceptions of the driving public. The Phase II responses from statewide surveys in Iowa, Minnesota, and Wisconsin address the topics of perceptions of the State Departments of Transportation (DOTs), pavement repair tradeoffs, and pavement evaluation. The results disclose specific public perceptions of priorities for spending limited highway funds. Implications for pavement management, policy, planning, as well as for marketing to garner additional funds are explored

    Energy and the State of Nations

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    The mathematical conditions for the existence of macroeconomic production functions that are state functions of the economic system are pointed out. The output elasticities and the elasticities of substitution of energy-dependent Cobb-Douglas, CES and LinEx production functions are calculated. The output elasticities, which measure the productive powers of production factors and whose numerical values have been obtained for Germany, Japan, and the USA, are for energy much larger and for labor much smaller than the cost shares of these factors. Energy and its conversion into physical work accounts for most of the growth that mainstream economics attributes to “technological progress” and related concepts. It decisively determines the economic state of nations. Consequences for automation and globalization and perspectives on growth are discussed.energy; economic growth; macroeconomic production functions; output elasticities

    A wide field survey at the Northern Ecliptic Pole: II. Number counts and galaxy colours in B_j, R, and K

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    We present a medium deep survey carried out in the three filters B_j, R and K. The survey covers homogeneously the central square degree around the Northern Ecliptic Pole (NEP) down to a completeness limit of 24.25, 23.0 and 17.5mag in B_j, R and K, respectively. While the near infrared data have been presented in the first paper of this series, here we concentrate on the optical data and the results based on the combined B_jRK-data. The unique combination of area and depth in our survey allows to perform a variety of investigations based on homogeneous material covering more than ten magnitudes in apparent brightness. We analyze the number counts for point-like and extended sources in B_j and R to determine the slopes in dlogN/dm and to test for possible breaks therein. While we can confirm the slopes found in previous works with a higher statistical significance, the largest uncertainty remaining for the amplitudes is galactic extinction. We determine the colour distributions of galaxies in B_j-R and R-K down to B_j=24.0 and K=18.0mag, respectively. The distributions in both colours are modeled using galaxy spectral evolution synthesis. We demonstrate that the standard models of galaxy evolution are unable to reproduce the steady reddening trend in R-K despite flawless fits to the colour distributions in the optical (B_j-R). The B_jRK data collected over a large area provides the opportunity to select rare objects like candidates for high-redshift galaxies and extremely red objects (EROs, R-K>5.0) and to determine their surface density. Our EROs are selected at an intermediate magnitude range and contain contribution from both galactic as well as extragalactic sources. At K<16.5mag, where a morphological classification is possible, the stellar component dominates the sample.Comment: Accepted for A&A, 14 pages, 10 figure

    Public Perceptions of the Midwest\u27s Pavements: Explaining the Relationship Between Pavement Quality and Driver Satisfaction

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    A three-phase study involving focus groups and sample surveys was conducted in three Midwestern states to assess the amount of satisfaction that motorists who drive on rural, two-lane state highways have with the pavement characteristics of those highways and to explain the relationship between the actual physical condition of the pavements and motorists\u27 satisfaction. Consistently in each state, the direct relationship between pavement quality and driver satisfaction was mediated by cognitive structure—a set of five specific beliefs motorists have about the pavement. The part of the study that (a) applies a powerful psychological model to the task of understanding motorists\u27 satisfaction with pavements; (b) offers reliable measures of driver satisfaction with pavement quality and of belief-based cognitive structure related to pavements; (c) has accomplished the important task of identifying the most salient pavement features considered by members of the public when they evaluate pavement quality; and (d) illustrates very clearly the importance of considering motorists\u27 beliefs about the pavement, issues of trust, and aspects of the Fishbein\u27s attitude model and Ajzen\u27s theory of planned behavior when trying to predict or understand driver satisfaction are covered. Although the pavement management indices used by the state departments of transportation will continue to be used to establish thresholds for improvement triggers, these indices alone do not explain such broad concepts as satisfaction with a particular pavement

    A global clean fossil scenario:discussion paper

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    Calculation fuel transport emission

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    Public Perceptions of the Midwest’s Pavements - Introduction

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    The “Public Perceptions of the Midwest’s Pavements” is the largest survey of public perceptions of satisfaction and improvement policies on rural, two-lane highways ever conducted in the 20th Century in the USA. The project was a Pooled Fund effort undertaken by the Wisconsin DOT and included equal participation of the Iowa and Minnesota DOTs. Approximately 4500 drivers and over 1000 highway segments were surveyed in the three states in all three phases of the project, between 1996 and 2000. The surveys included improvement policy and construction alternative issues and trade-offs, as well as surveys of beliefs and attitudes of the public that affect public trust and satisfaction. The results of the project are reported in phase reports (pdf), with a report on each phase in each state
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