| Summary: | 碩士 === 逢甲大學 === 運輸科技與管理學系 === 101 === Highway traffic noise has gradually become an annoying and severe environmental problem in highly developed countries during past decades. Efforts for reducing such a problem, such as streamlined vehicle shape, noise barriers, traffic control strategies, appropriate urban planning and land use, and pavement modification, have been proposed and enforced. However, none of the above mentioned efforts are universal solutions. They may be good for one case, yet may be of no use for another. Moreover, effects of these strategies are not fully identified. There is a need to verify effect of each strategy to give a better estimate for overall effect of a combination of noise reducing strategies. In this study, effect of pavement character on traffic noise is of interest. In-situ pavement characters, traffic noise volume, and noise frequency spectrum were measured at appropriate test sites on national freeway 1, 3, 4, and 6. Statistical analysis was then performed to analyze correlation of these factors. Noise measurement were performed following ISO 11819-1, meanwhile pavement characters measurement were performed according to ASTM, ISO, and JIS standards. Through regression analysis, correlations between various pavement characters and traffic noise were established. It is found that average 1~2 dBA noise reduction may be obtained for every 10 km/hr speed reduction for most of the highway pavements tested. Yet a 3 dBA reduction per 10 km/hr speed reduction at some pavements was also observed. Moreover, vehicle type is the key factor that influences traffic noise of flexible pavement, whereas average grinding depth is that for rigid pavement.
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