ON THE NOISE GENERATED BY A STREAM OF VEHICLES

THE NOISE GENERATED BY A STREAM OF TRAFFIC IS CONSIDERED USING AS A MODEL, A STREAM OF SIMPLE ACOUSTIC SOURCES. IN CONTRAST TO AN EARLIER ANALYSIS, THE POSSIBILITY OF A NEGATIVE EXPONENT HEADWAY DISTRIBUTION BETWEEN SUCCESSIVE CARS IS ALLOWED. THE MODEL IS SHOWN TO BE EQUIVALENT TO A SHOT PROCESS, AND THE CUMULANTS ARE READILY CALCULATED. IF TRAFFIC CONSISTS OF SEVERAL TYPES OF VEHICLES, EACH TYPE GENERATING NOISE OF A DIFFERENT INTENSITY, THEN IN THE LOW DENSITY REGIME THE TRAFFIC CAN BE REPRESENTED BY A SUPERPOSITION OF NONINTERACTING ACOUSTIC SOURCES. MODIFICATIONS OF THE SHOT NOISE MODEL CAN BE MADE TO TAKE INTO ACCOUNT SURFACE GRADIENTS OR SOUND-ABSORBING SURFACES BY A SUITABLE DISTRIBUTION OF ACOUSTIC SOURCES. /AUTHOR/