Road traffic is the primary source of unwanted outdoor noise caused by human activity. It has been linked to a range of adverse outcomes, from short-term effects, such as sleep disturbance and reduced cognitive performance, to long-term chronic diseases. The pathways by which noise exposure impacts health and well-being extend beyond the physiological act of hearing, as the auditory perception is highly subjective, personal, and context-dependent. Yet, noise control regulatory frameworks typically limit their scope to reducing exposure, thereby neglecting key characteristics of the acoustic environments and situational aspects. Beyond noise levels, spectral content, temporal dynamics, noise source composition, and several non-acoustic modifiers can jointly determine the perceptual and physiological burden of environmental noise. This thesis addresses road traffic noise as a component of the broader environmental noise context, investigating the interplay between its measurable acoustic features, geospatial and contextual information, and the perceptual, behavioral, and physiological responses of individuals and the community. Firstly, vehicle noise was characterized using psychoacoustic indicators, which are objective metrics that better resemble the human auditory experience. These indicators were found to vary systematically with driving speed and temperature and to produce distinctive acoustic signatures for different vehicle classes. Used as features in an audio-only vehicle classifier, psychoacoustic indicators enabled 91% accuracy, offering a potential shift toward a vehicle classification based on how vehicles “sound like” rather than visual characteristics. Second, longitudinal field studies showed that community acceptance of large infrastructural road-noise interventions (noise barriers and road resurfacing with low-noise asphalt) depends less on the eventual noise levels than on situational factors such as trust in the road authorities and expectations. Third, an immersive laboratory experiment combining auralized tire-road noise with virtual-reality streetscapes demonstrated that lower speed limits, quieter and well-maintained pavements, and, to a lesser extent, green infrastructure, reduce not only self-reported noise annoyance but the involuntary physiological stress response, as measured by biomarkers. Finally, a dataset of geolocated soundwalks collected through a citizen science initiative was used to explore the impact of the physical environment on the subjective soundscape assessments. Indicators of anthropogenic activity, presence of nature and land use, and traffic infrastructure proved to explain, to a modest extent, the variance in pleasantness and eventfulness in everyday settings. A prototype geospatial model based solely on these variables shows potential for scalability and replicability, offering a practical tool to guide large-scale soundscape interventions.
Read more