Temporal and Spatial Factors of Traffic Noise and Its Annoyance

Abstract

This paper describes and demonstrates procedures for indexing temporal and spatial factors of traffic noise, and report a laboratory experiment investigating the relationship between these indices and subjective annoyance with the noise. Primary sensations (loudness, pitch, timbre) and spatial sensations (source location, diffuseness, source width) of sounds are described by the autocorrelation function (ACF) and the inter-aural cross-correlation function (IACF) respectively. Especially, we focused on the primary sensations of traffic noise in relation to the subjective annoyance. A laboratory experiment was designed to examine the validity of the proposed noise indices described in terms of the ACF. Scale values of subjective annoyance were measured by paired comparison. Results showed that the effects of temporal fluctuation of sound level, tonal properties, and fluctuation of pitch become significant predictors of annoyance when the subjects heard various types of traffic noise with equal listening level. Contributions of these parameters correspond with earlier findings relating to annoyance. Thus, the results suggest that the proposed ACF factors can be possible measures to evaluate perceived annoyance in addition to the overall SPL.