Levels and Spectra of Transportation Vehicle Noise

Abstract

In the recent past a program was initiated to survey vehicle, traffic, and industrial noise in the Chicago area. The phase on noise of vehicles has been completed. The investigation included street, elevated, and subway cars; diesel, steam, and electric trains; and motor buses, trucks, and automobiles. Measurements were made of over-all and octave band levels. Inside of the vehicles, flat network over-all levels ranged from 85 db in a new “L” car to 95 db in subway cars. The readings in the 400–800 c.p.s. band ranged from 68 db in an automobile to 91 db in subway cars. Outside of and close to vehicles, the flat network over-all levels ranged from 78 db for automobiles to 94 db for subway trains. Observations in the 400–800 c.p.s. band ranged from 66 db for automobiles to 87 db for subway trains. Variations in the over-all levels inside of vehicles ranged from ±1 to ±5 db. Variations the 400–800 c.p.s. band ranged from ±2 to ±5 db. Outside of the vehicles, variations ranged from ±2 to ±6 db in both the over-all and 400–800 c.p.s. band levels.