A measuring instrument for the perceptual dimensions of road traffic noise

Road traffic, especially in urban environments, is one of the major sources of our everyday soundscape and its impact on human well-being and health is well documented. While most studies have used perceived annoyance as an indicator of perceptual impact, little is known about the dimensions that define the perceptual space evoked by the different characteristics of road traffic noise and the acoustic correlates of these dimensions. Therefore, the present study developed a psychological instrument to measure the qualities of road traffic noise. Based on a sample of contrast pairs created from third-order Ambisonics recordings of various traffic scenes in and around Berlin and reproduced in the laboratory, attributes were elicited using a standardized but open-ended procedure. Subsequently, 45 of the recorded traffic scenes were rated by 115 participants using a redundancy-adjusted set of attributes. Exploratory and confirmatory factor analyses of the questionnaire data yielded two optimal solutions with five and seven factors spanning the perceptual dimensions. The resulting psychometrically validated instruments, in the form of 15-item and 21-item questionnaires, can be used for the perceptual assessment and for the further development of technical parameters to predict not only annoyance but also other salient qualities of traffic-related soundscapes.