Street-level noise assessment across different urban block typologies: a voxel-based forward ray tracing model

Urban noise pollution is a growing concern with significant implications for public health and urban livability. This study introduces a voxel-based forward ray tracing (V-FRT) method to investigate how different types of urban block design may impact street-level noise distribution. Nine urban block scenarios were simulated by considering the various building types and densities. V-FRT was implemented in Grasshopper Rhino to estimate noise propagation from urban traffic. The results show that dense and enclosed urban design, particularly high-density perimeter blocks, is conducive to noise concentration, resulting in the largest proportion of urban space being exposed to noise levels exceeding 55 dB. In contrast, open configurations, such as low-density single-building blocks, tend to facilitate noise reduction. It was also found that the noise level is consistently the highest up to two meters above the urban streets, which is the primary space where most people conduct their outdoor activities. The study demonstrates the V-FRT model’s ability to capture both horizontal and vertical patterns of noise distribution, providing a scalable approach for assessing urban noise environments. It demonstrates that urban design choices can significantly reduce or increase noise exposure, underscoring the importance of urban design in promoting healthy cities.