Investigations on road traffic noise based on an exponentially distributed vehicles model—single line flow of vehicles with same acoustic power
✍ Scribed by K. Takagi; K. Hiramatsu; T. Yamamoto; K. Hashimoto
- Publisher
- Elsevier Science
- Year
- 1974
- Tongue
- English
- Weight
- 654 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0022-460X
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✦ Synopsis
Statistical properties of road traffic noise have been investigated, based on a model in which point sources of the same acoustic power are distributed on an infinite line in such a way that the spacing between successive point sources has, as a probability density function, an exponential distribution. The basic parameters in the model are S and d, where S is the average spacing between successive vehicles and d is the perpendicular distance from an observation point to the line. The characteristic function, exp [K(u)], of sound intensity at an observation point was approximated by a function, exp[Kl(u)], which depends on a parameter =[0 < ~ < 1] as well as on S and d. As a result, Kl(u) was chosen so that Kl(u) coincides with K(u) at d --+ 0 and d ~ co and also/1 coincides with/'where/-~ and/-are the means of the sound intensities determined by Kl(u) and K(u), respectively. From this approximate characteristic function, the probability density function (pdf), mean and variance of the sound pressure level (SPL) were derived. The value of = was determined as a function of diS from the results of simulated calculations by means of a Monte Carlo method. The pdf, and the mean and the variance of the SPL thus obtained were in good agreement, respectively, with the histogram, the mean and the variance of the SPL obtained from simulated calculations. Comparisons are shown between th e present results and those of previous investigators.