Effects of road traffic background noise on judgments of individual airplane noises

Two laboratory experiments were conducted to investigate the effects of road-traffic background noise on judgments of individual airplane flyover noises. In the first experiment, 27 subjects judged a set of 16 airplane flyover noises in the presence of traffic-noise sessions of 30-min duration consisting of the combinations of 3 traffic-noise types and 3 noise levels. In the second experiment, 24 subjects judged the same airplane flyover noises in the presence of traffic-noise sessions of 10-min duration consisting of the combinations of 2 traffic-noise types and 4 noise levels. In both experiments the airplane noises were judged less annoying in the presence of high traffic-noise levels than in the presence of low traffic-noise levels

Traffic Noise and the Hyperbolic Plane

We consider the problem of sound propagation in a wind. We note that the rays, as in the absence of a wind, are given by Fermat's principle and show how to map them to the trajectories of a charged particle moving in a magnetic field on a curved space. For the specific case of sound propagating in a stratified atmosphere with a small wind speed we show that the corresponding particle moves in a constant magnetic field on the hyperbolic plane. In this way we give a simple `straightedge and compass' method to estimate the intensity of sound upwind and downwind. We construct Mach envelopes for moving sources. Finally, we relate the problem to that of finding null geodesics in a squashed anti-de Sitter spacetime and discuss the $SO(3,1)\times \mathbb{R}$ symmetry of the problem from this point of view.Comment: Typos correcte

Noise event measures for road traffic

How should noise events in road traffic noise be measured? This paper reports the performance of a set of algorithms that detect noise events in time histories of road traffic noise in the population of acoustic conditions found near roadways. The latter was obtained through simulation of 500 different road traffic noise time histories using a comprehensive range of traffic flow, traffic composition, and propagation distance, conditions in unshielded locations near roadways. The initial set of algorithms tested was developed by systematically expanding on threshold-based algorithms described in the literature, then excluding those that were unreliable. The finding was that the NA50 and NA55 (detecting when road traffic noise exceeded 50 dB and 55 dB respectively), and the NAL50E10 (detecting when the traffic levels exceeded L50 + 10 dB) can all be considered for practical application as event detection indicators. All apply to measurement of indoor events with the windows of the dwelling open. The primary criterion for selection as supplementary indicators (and others in the same clusters that could substitute for them) was their non-monotonic relationship with the LAeq, The traffic and distance conditions under which these event-based measures could potentially be useful supplementary indicators is identified.Griffith Sciences, Griffith School of EnvironmentFull Tex

Stated choice valuation of traffic related noise

This paper reports a novel application of the stated choice method to the valuation of road traffic noise. The innovative context used is that of choice between apartments with different levels of traffic noise, view, sunlight and cost with which respondents would be familiar. Stated choice models were developed on both perceived and objective measures of traffic noise, with the former statistically superior, and an extensive econometric analysis has been conducted to assess the nature and extent of householders’ heterogeneity of preferences for noise. This found that random taste variation is appreciable but also identified considerable systematic variation in valuations according to income level, household composition and exposure to noise. Self-selectivity is apparent, whereby those with higher marginal values of noise tend to live in quieter apartments. Sign and reference effects were apparent in the relationship between ratings and objective noise measures, presumably reflecting the non-linear nature of the latter. However, there was no strong support for sign, size or reference effects in the valuations of perceived noise levels

Measurement of noise events in road traffic streams: initial results from a simulation study

A key question for road traffic noise management is whether prediction of human response to noise, including sleep quality, could be improved over the use of conventional energy equivalent, or percentile, measures, by accounting for noise events in road traffic streams. This paper reports initial results from a noise-events investigation into event-based indicators over an exhaustive set of traffic flow, traffic composition, and propagation distance, conditions in unshielded locations in proximity to roadways. We simulate the time-varying noise level histories at various distances from roadways using a dynamic micro-traffic model and a distribution of sound power levels of individual vehicles. We then develop a comprehensive set of noise event indicators, extrapolated from those suggested in the literature, and use them to count noise events in these simulated time histories. We report the noise-event algorithms that produce realistic, and reliable, counts of noise events for one-hour measurement periods, then reduce redundancy in the indicator set by suggesting a small number of representative event indicators. Later work will report the traffic composition and distance conditions under which noise event measures provide information uncorrelated with conventional road traffic noise indicators — and which thus may prove useful as supplementary indicators to energy-equivalent measures for road traffic noise

Treatment of road traffic noise in EU countries with a focus on Directive 2002/49/EC

The trend of continuous increase for mobility requirements results in a progressive increase in the use of vehicles of all modes of transport, which contributes to a significant increase in noise levels, especially in urban areas. The most significant noise in urban areas is traffic noise, where road traffic contributes the most. This paper reviews the treatment of road traffic noise in the European Union with a focus on Directive 2002/49 / EC. The paper presents the basics of the mechanisms of the institutional and management framework in the field of road traffic noise monitoring in EU countries. Also, the results of road traffic noise monitoring in EU countries, indicators of population exposure to road traffic noise, as well as indicators of the impact of road traffic noise on the health of the population, were presented

Spatial Analysis of Urban Form and Pedestrian Exposure to Traffic Noise

In the Macao Peninsula, the high population density (49,763 inhabitants/km2) and the lack of control over the number of vehicles (460 vehicles/km) have led to an increase in urban pollution. To provide useful information to local government and urban planners, this paper investigates the spatial distribution of traffic noise in the Macao Peninsula. The interactions among urban form, traffic flow and traffic noise are addressed. Considering the spatial nature of urban geometry and traffic, a high-resolution GIS-based traffic noise model system is applied. Results indicate that the Macao Peninsula has fallen into a situation of serious traffic noise pollution. About 60% of traffic noise levels along the major pedestrian sidewalks in the evening peak hour exceed the National Standard of 70 dB(A) in China. In particular, about 21% of traffic noise levels along the pedestrian sidewalks are above the National Standard by 5 dB(A). Noticeably, the high pedestrian exposure to traffic noise in the historical urban area reduces the comfort of tourists walking in the historic centre and is ruining the reputation of the area as a World Cultural Heritage site

Effects of Experimentally Elevated Traffic Noise on Nestling White-Crowned Sparrow Stress Physiology, Immune Function and Life History

Roads have been associated with behavioral and physiological changes in wildlife. In birds, roads decrease reproductive success and biodiversity and increase physiological stress. Although the consequences of roads on individuals and communities have been well described, the mechanisms through which roads affect birds remain largely unexplored. Here, we examine one mechanism through which roads could affect birds: traffic noise. We exposed nestling mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) to experimentally elevated traffic noise for 5 days during the nestling period. Following exposure to traffic noise we measured nestling stress physiology, immune function, body size, condition and survival. Based on prior studies, we expected the traffic noise treatment to result in elevated stress hormones (glucocorticoids), and declines in immune function, body size, condition and survival. Surprisingly, nestlings exposed to traffic noise had lower glucocorticoid levels and improved condition relative to control nests. These results indicate that traffic noise does affect physiology and development in white-crowned sparrows, but not at all as predicted. Therefore, when evaluating the mechanisms through which roads affect avian populations, other factors (e.g. edge effects, pollution and mechanical vibration) may be more important than traffic noise in explaining elevated nestling stress responses in this species

Estimating the effect of semi-transparent low-height road traffic noise barriers with ultra weak variational formulation

The ultra weak variational formulation (UWVF) approach is used to study the effect of semi-transparent road traffic noise barriers of limited height. This numerical method is extended to simulate sound propagation through a porous medium, based on the Zwicker and Kosten phenomenological porous rigid-frame model. An efficient approach to calculate noise levels in multi-lane road traffic noise situations is presented. The UWVF method was validated successfully by comparison with finite-difference time-domain (FDTD) calculations, for the case of sound propagation near a porous, low-height, and complex shaped noise barrier, and for sound propagation above porous ground in a refracting atmosphere. An assessment is made of the shielding of various porous low-height noise barriers for people on the pavement along the road. Porous barriers were shown to improve noise shielding when compared to geometrically identical rigid noise barriers

Effects of street traffic noise in the night

The relationship between automobile traffic noise and the degree of disturbance experience experienced at night was explored through a random sample survey of 1600 individuals in rural and urban areas. The data obtained were used to establish threshold values