Modeling and Mitigation of Road Traffic Noise in a Major Hub for Urban Sustainability: A Case Study of Kocaeli, Türkiye

The aim of this study is to model traffic noise from the D-100 (a major national highway) and TEM (Trans-European Motorway), a major hub in Türkiye. This study models traffic noise from the D-100 and TEM using SoundPLAN software (NMPB-96 methodology) to identify legal levels and evaluate mitigation strategies. The model was verified locally with absolute errors of 1.3–1.7 dB(A). Impact analyses based on the Lden and Lnight (Ln) indicators have revealed that sensitive areas (e.g., dwellings, schools and hospitals) are exposed to noise levels that considerably exceed legal limits, primarily due to heavy vehicle traffic during the night-time hours. Two different noise mitigation scenarios were applied to the baseline model for addressing noise exposure. As a result, noise levels were reduced by approximately 4 dB(A). The number of residences exposed to excessive noise above 75 dB(A) decreased from 10,898 to 4451 (59%). A significant increase in acoustic comfort is achieved by reducing the number of dwellings in the 70–75 dB(A) contour range during night-time hours. The results indicate the need for integrated traffic management and infrastructure improvements for sustainable urban noise control.