Sound-pressure analyses of noise from motor vehicles

A number of different motor vehicles have been tested under standardise d conditions. The vehicles were chosen as to be representative for the vehicles in use in Sweden.

60 new vehicles of different kinds were tested and dB (A), dB (B), dB (C), sone and phon values for these are presented. It has been found that the frequency spectra are very similar within each category of vehicle e.g. private car, bus, truck, motorcycle scooter and motor-assisted cycle. Mean frequency spectr a with mean deviation are showed for these categories.

Also 105 used vehicles were tested and it was found that age had very little influence on the noise emitted, except for motor-assisted cycles, among which the sound level increased with age, but this fact is definitely due to better mufflers and construction on the latest models.

It was also found that the frequency spectra were not changed by age for 21 private cars of similar model of 0 to 5 years of age.