Showing papers on "Noise barrier published in 1981"

Highway noise, noise mitigation, and residential property values

Abstract: This paper presents the findings of a study of the relationship between different noise levels and market values for a sample of 206 single-family residences abutting Interstate-495 in Northern Virginia and for a sample of 207 residences along two heavily traveled urban streets in the Tidewater area of Virginia. Estimates of the influence of noise on the market price of houses sold in 1978-1979 at these sites, where barriers have since been completed, were then used to estimate economic benefits received by property owners. By using these estimates, it was concluded that recent public expenditures on highway noise abatement per household far exceed reasonable economic benefit levels, even for noise reductions of 10 dB(A). (Author)

Highway noise barriers

Abstract: This summary of progress on highway noise barriers gives quantitative and qualitative perspectives of the design, construction, maintenance, and impacts of the barriers that have been built to mitigate excessive highway noise. The Federal Highway Administration (FHWA) design noise levels are the principal criterion used to determine height and length of a barrier. Most states will not install a barrier unless it will result in a noise reduction of at least 10 dBA (some use 5 dBA as a minimum). Most states use the FHWA model for highway noise prediction, and two thirds of the states design for the most critical receptor. Systematic procedures to obtain data on impacts on residents and motorists are discussed. The perceived effectiveness is often influenced by aesthetics and landscaping of a barrier rather than by acoustical performance. Maintenance problems of barriers include difficulty with mowing close to barriers, litter accumulation, graffiti, and vandalism. Several states have developed priority rating systems for installing noise barriers on existing highways. Design details as well as construction and maintenance aspects are covered in this report. It is recommended that states seek innovative ways to reduce mass of barriers while maintaining noise reduction capability.

Role of plant materials in traffic noise control

Abstract: The primary objective of this series of studies was to determine the extent to which plant materials are capable of reducing intrusive noise, mainly that from traffic. Tape-recorded sound and live sound were used for noise sources. Measurements were made by direct instrument reading and by magnetic-tape recording. Distances in the range of 5-122 m (16-400 ft) were used. Several kinds of trees and shrubs alone and combined with solid barriers were studied. More than 20,000 individual readings were taken in the three series of experiments; the minimum was 4 and the maximum was 12 readings at each position. Each experimental point shown on the graphs represents averages of eight or more readings. Although varying atmospheric conditions pose difficulties in the measurement of outdoor sound, the reduction of sound is less affected by the insertion of barriers than the individual day-to-day measurements are; under similar atmospheric conditions, measurements were repeatable within 1 or 2 dB. Readings much beyond 91 m (300 ft) from the noise source were subject to large atmospheric-induced fluctuations of sound level and are considered less reliable than are closer readings. Results indicate that plant materials can be used effectively to reduce intrusive noise under certain conditions. They are not a panacea, however, and considerable knowledge based on experience is needed for proper application. Perhaps the best use, in the majority of cases, is a combination of trees and some form of solid barrier. Three series of experiments, which span an eight-year period, serve as the basis for this paper. (Author)

Sensitivity of predicted barrier attenuations to errors in specifying ground plane geometry

Abstract: When the ground behind a noise barrier may be regarded as acoustically locally reacting, and where it has reasonably level topography, there is a plausible rationale for a traffic noise prediction model based on barrier diffraction of geometric image terms with coherent summation. Often in real life, however, even when sideline terrain surface is essentially plane, its plane is neither coplanar with the highway pavement nor even parallel to it. Defining the ground “plane” from measurements on the site, moreover, is not a task likely to be done with great precision in normal noise assessment practice. The sensitivity of traffic noise level predictions to errors in ground‐plane location then becomes of interest. In this connection a study has been made of a series of ground‐plane configurations approximating to cases arising in practice. Each case has been perturbed systematically, and the resulting differences in predicted noise levels have been observed. It has been particularly of interest to note the decrease in sensitivities resulting from averaging over frequency and over a traffic line. [Work supported by FHWA.]

Noise barrier wall

Abstract: A noise and visual barrier wall (1), which can be employed in particular as a screen for the noise produced by road and/or rail vehicles, is composed of one or more absorbers arranged above or next to one another for absorbing or releasing heat energy, or one or more outsides of a single- or multi-component barrier wall are designed as absorbers. The absorbers (11) here consist of profiled lamellae (12), which are put in adjacent rows and/or arranged above one another, preferably cover one another partially, and are connected to one another via collecting pipes (14) and/or via a heating or cooling circulation. The noise and visual barrier wall formed in this way thus serves not only for sound damping, but also at the same time for absorbing or releasing heat energy. By means of this configuration, it is then possible with little structural outlay, in particular without having to erect additional, mostly disruptive structures, for absorbers to be installed in a simple manner and for these to be used to exploit available heat energy. An apparatus is thus provided by means of which an effective barrier against noise is achieved with only a little more expenditure, an additional refraction of sound waves being produced by the absorbers and available heat energy additionally being exploited.

Analysis of traffic noise abatement strategies

Abstract: Computer simulations of traffic sound levels were performed to evaluate the probable effectiveness of several hypothetical noise abatement strategies in reducing residential exposure to traffic sound. These simulations were performed for 28 actual census tracts in six cities which were chosen to be representative of the urban United States. Results showed that limits on noise levels during acceleration for new automobiles would have only a small effect on traffic noise exposure, while limits on truck‐acceleration noise levels would have a greater effect. Nonresidential zoning along arterials was calculated to have a greater effect than automobile‐noise limits, but a smaller effect than truck‐noise limits. A hypothetical vehicle fleet including large proportions of four‐cylinder and diesel‐powered automobiles was calculated to produce slightly greater residential noise exposure than at present.

Problems of noise and vibration due to railway traffic in the urban environment; systems of protection

Abstract: A description of techniques applied by the RATP (Paris Transport Authority) to reduce and virtually eliminate disturbance caused to people living in the vicinity through propagation of noise (reduction of noise at its source and prevention of its propagation by means of sound barriers) and through transmission of vibrations (reduction of vibration at the source and protection against its transmission between the underground structure and nearby buildings, and between the rail and the underground structure).