Statistical Study of Traffic Noise

Abstract

To provide the necessary data for noise-abatement programs, a comprehensive study of motor vehicle noise is being conducted. The concept of noise as a form of environmental pollution is accepted as basic, and the noise output of motor vehicles is regarded as a function of the vehicle-driver combination, rather than of the vehicle alone. The noises from more than 2000 vehicles have been recorded on tape and analyzed for over-all dB, dBA, and in octave bands from 31.5 to 8000 Hz. For passenger cars, the peak of the noise-level distribution lies at about 65, 67, 72, and 73 dbA for the speed ranges of 30–39, 40–49, 50–59, and 60–69 mph, respectively, at a measuring distance of 15 m. The values for dump trucks, the noisiest of the heavy trucks, are about 10 dB higher when empty, and 12 or 13 dB higher when loaded. The values for tractor trailers are about 15 dB higher. The scatter for passenger cars is about 10 dB, and somewhat greater for trucks and tractor trailers. Motorcycles may be the noisest of all.

Some exact distributions in traffic noise theory

“…A great deal of data is available e.g. Olson [10], [11] and Lewis [7]. Such data is conventionally fit by a normal distribution for L, i.e.…”