| 摘要 |
PROBLEM TO BE SOLVED: To reduce sizes and to conduct measurement of an excellent S/N ratio, as to a road face drainability measuring instrument for measuring drainability on a road face, and a road face drainability measuring vehicle mounted with the road face drainability measuring instrument, and traveling on the road face to measure the drainability on the road. SOLUTION: This instrument is provided with a sound insulated box 10 of which the one face is opened and of which the inner wall is covered with a sound absorbing material 12, a speaker 13 for emitting a pulse sound into the sound insulated box toward an opening 11, and a micro-phone 14 arranged in the midway position between the speaker and the opening in the sound insulated box, and for detecting both pulse sounds of a direct sound emitted from the speaker and before reaching to the road face, and a reflected sound emitted from the speaker and reflected on the road face to get incident from the opening. Based on the respective direct sound and reflected sound, a value serving as an index for the drainability of the road face is found from signals of at least partial frequency bands out of frequency bands from 5 kHz or more to 40 kHz or less.
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