# Traffic Noise Reduction Strategy in a Large City and an Analysis of Its Effect
###### Abstract  
A noise reduction strategy was proposed for Panyu District of Guangzhou City based on its traffic noise map, which considered both road and railway traffic noise. Commercial software was applied to compute the noise maps with and without noise barriers based on the field traffic flow measurements. Noise compliance maps were further developed to assess the effects of noise barriers on the quality of the sound environment. The change in populations exposed to unhealthy traffic noise with noise barriers was calculated, and the group noise indicators \(G_{dn}\) and \(G_{night}\), which indicate the populations of highly annoyed and sleep-disturbed people, were evaluated. The results showed that the traffic noise level was significantly decreased after the implementation of noise barriers. It was predicted that with the strategy of applying suitable noise barriers, the overall areas under heavy noise pollution could be reduced by 24.5 and 24.3 km\({}^{2}\) during daytime and nighttime, respectively. Meanwhile, the total areas that could meet the regulated standard for noise levels were increased by 97.4, and 66.9 km\({}^{2}\), corresponding to compliance rate increments of 18.38% and 12.62%, respectively, in daytime and nighttime. The results further revealed that the installation of noise barriers could significantly reduce the population of highly annoyed people, while the reduction of the population experiencing sleep disturbances was insignificant. traffic noise map; noise barrier; noise limit; compliance rate 2022  
[PERSON]; [PERSON]; [PERSON]; [PERSON] Traffic Noise Reduction Strategy in a Large City and an Analysis of Its Effect. _Appl. Sci._**2022**, _12_, 6027. [[https://doi.org/10.3390/app12126027](https://doi.org/10.3390/app12126027) Academic]([https://doi.org/10.3390/app12126027](https://doi.org/10.3390/app12126027) Academic) Editors: [PERSON], [PERSON] and [PERSON] Received: 5 May 2022  
Accepted: 11 June 2022  
to populations having strongly detrimental emotions, such as those of hostility, anger, and helplessness. [PERSON] et al. [8] investigated the effect of road traffic noise on the incidence of myocardial infarction. The results showed that the odds ratio of men being exposed to noise levels beyond 70 dBA during daytime was 1.3, as compared to those exposed to noise levels of less than 60 dBA. It was discovered that chronic exposure to high levels of traffic noise could lead to a high risk for cardiovascular disease. [PERSON] et al. [9] investigated the effects of railway and road traffic noise on the blood pressure of an exposed population. It was revealed that transportation noise may exert severe health effects on vulnerable populations, such as adults with hypertension, diabetes, or cardiovascular disease. [PERSON] et al. [10] also found that exposure to traffic, airport, and recreational noise also led to an increase in diastolic blood pressure and hypertension problems. Among the various sources of noise, railway noise was reported to have the most significant impact on diastolic blood pressure. In order to explore the relationship between annoyance and traffic noise levels, research was carried out to correlate annoyance indexes and noise levels. [PERSON] and [PERSON] [11] developed a model that correlated the annoyance scale and noise exposure level. The day-night level (DNL) and day-evening-night level (DENL) were used as the noise descriptors. The results showed that the developed model could fit the experimental data with high confidence intervals. In an effort to evaluate annoyance due to overall railway noise and vibration, [PERSON] et al. [12] further considered the effects of \"unconventional railway noise\" sources, such as braking, squeals, whistles, screeching, etc. They found that railway noise's impact on the disturbance of people was generally underestimated and that the existence of unconventional railway noise increased annoyance during both the daytime and the nighttime.