# Traffic Noise Reduction Strategy in a Large City and an Analysis of Its Effect
###### Abstract
Traditional noise maps that were developed based on ordinary transits were usually biased toward the epidemiological studies of railways, and it has been suggested that the accuracy of noise maps can be improved by considering unconventional noise sources. In addition, environmental noise also has a significant impact on humans' cognitive and learning abilities, particularly for vulnerable groups, such as infants and young children. [PERSON] et al. [13] experimentally investigated the effects of low-frequency noise on human cognitive performance among 25 participants, including male and female volunteers of the ages of 19-29. The results showed that under noisy conditions, people's stress was obviously enhanced, and their response time was decreased in comparison to that under silent conditions. [PERSON] et al. [14] reviewed the overall consequences of background noise on the health, perception, cognition, and learning of infants and children. They found that background noise can particularly lead to disadvantageous effects on infants' and young children's recognition and learning from speech. [PERSON] et al. [15] investigated the noise levels of the neonatal helmets applied in respiratory support for preterm infants. The noise levels of the respiratory system were found to exceed the recommendations by reputable organizations, and filters with higher flow resistance were the cause of the higher noise levels created in the neonatal helmets. Hence, for the goodness of the preterm infants' health, the sound performance of respiratory systems should be carefully considered during the design of products. [PERSON] et al. [16] investigated the annoyance index with respect to environmental noise in students in secondary schools in Italy by using questionnaires. The acoustic environment in the classroom was found to have significant influences on students' speech listening and comprehension, and, hence, it negatively affected their educational performance. Aside from public health, the existence of traffic noise also exerts a significant impact on house prices. [PERSON] [17] developed an empirical analysis of traffic noise with respect to the value of single-family properties. The hedonic price method was applied by assuming that the negative externalities could be translated into property values. The results indicated that the effects of traffic noise on property values were negative. They found that the depreciation of the values of single-family houses due to noise pollution could be as high as 30%. [PERSON] [18] found that, in the Netherlands, the noise level could be translated into property prices when it exceeded 65 dBA, and the maximum discount of the property prices could be up to 12% because of noise. However, the properties in places where the noise levels were less than 40 dB could be sold with a premium of up to 6.5%. [PERSON] and [PERSON] [19] applied spatial hedonic models to analyze the impact of airport noise on the house prices near the Atlanta airport. They found that the house prices in areas where the day-night noise level disrupted normal activities (70-75 dBA) were 20.8% lower than those in areas where the day-night noise level did not disrupt the normal activities of people. [PERSON] et al. [20] investigated the effects of road traffic noise and railway noise on the property prices in Sweden. A hedonic regression analysis implied the strong negative impact of traffic noise on the property prices. The impact of road traffic noise was more significant due to the fact that people were more disturbed by road traffic noise than that of railways. [PERSON] and [PERSON] [21] further investigated the reaction of property prices to an airport expansion according to the planned flight paths. They found that the property listing prices of the areas impacted by the flight paths were greatly influenced after the flight paths were published. The average loss of value of the affected properties was as much as 9.6% when the slant distance between the affected areas and the flight paths was within 3 km.