A Revision on Mandatory Microphone Positions in the ISO11819-2 for Different Pavement Surfaces based on Noise Emission Characteristics

The ISO 11819-2 stipulates that at least two microphones shall be mounted on the side of the tire regardless of the pavement types. However, since the noise emission mechanism on the different road surfaces is vary, the proper microphone positions also need to be changed. In this study, we tried to suggest optimal microphone positions for different pavement surfaces based on noise emission level. Pavement types for comparison was defined as a general Dense Asphalt Concrete (DAC) and a porous type pavement (two-layer low noise pavement). While the microphone measuring positions for comparison were defined as the ISO11819-2 mandatory positions No. 1 and 2 representing side position, and the other one is No. 5 representing rear position respectively. The analysis results showed that noise level at rear position was higher on the general DAC surface type, while side positions were higher on the porous type pavement. Thus, this study suggested that microphone position No. 5 in the ISO 11819-2 would be better for noise measurement of the general DAC type pavement.