Abstract:
This study had two objectives: 1) to measure road traffic noise levels and to analyze relationship between the measured noise level and road traffic activities in an urban area of Nakhon Pathom province and 2) to analyze relationship between the road traffic noise and annoyance of people, as well as relationship between such annoyances and demographic information. Noise measurements were carried out over 24 hours at roadsides in a number of ten roads, together with questionnaire observation involving 360 subjects. Traffic activities were also recorded, using camera recorders, parallel to noise measurements. The recorded data were used to quantify vehicles types and their numbers. The results found that 24-hours-averaged noise levels (Leq,24h) of all ten roads were in the range of 61.7-81.8 dBA. Three of them had Leq,24h , ranged from 72.3-81.8, exceeding the standard of 70 dBA. For vehicle number counting, the top three vehicle categories were passenger car, pick-up and motorcycle, respectively. As for the traffic volume ratio (V/C ratio) of each measurement point, it is found that most of the services were in the A and B categories implying dexterous traffic movement. The analysis of correlation between total number of vehicles and noise levels resulted statistically correlated at a significant level of 0.01 with R = 0.840. For correlation analyses among measured noise levels and segregated vehicle categories, it found that the highest degree of correlation to noise levels were motorcycles (R2 = 0.978), followed by pick-up, truck, passenger car, van and bus (R2 = 0.839, 0.821, 0.815, 0.7840 and 0.738, respectively). For correlation of noise level modelled by CRTN model compared with measured noise levels, it resulted statistically correlated at a significant level of 0.01 with a mean difference of +1.38 dBA. Considering the relationship between daynight equivalent sound level (Ldn) and percentage of highly annoyance among genders, it indicates that female had the annoyance related with Ldn with significant level of 0.01, while it was found for male with no statistical significant.