| 摘要 |
PROBLEM TO BE SOLVED: To simplify the constitution, to widen the detection range, and to lower the cost by deciding a road surface state according to the water film thickness found by substituting meteorological quantities measured by meteorological sensors installed nearby the road in specific relational expressions. SOLUTION: The meteorological sensor consisting of a thermometer 1, a rain gauge 2, and a pysheliometer 3 are installed nearby the road 4. Meteorological data obtained by the sensors 1 to 3 are transmitted to an information gathering device 7. A road surface state decision device 8 performs a road surface deciding processing based upon those meteorological data and outputs the result to a display device 9. The decision device 8 decides the road surface state according to the water film thickness t' found by substituting those meteorological data in the relational expressions, i.e., water film thickness t=f (rainfall, road surface coefficient) and t'=t-(k0.N(1-R)+Q1+V1.(T0-Tx)). Here, N is the solar radiation quantity, R an albedo (reflection factor of road surface), Q1 sensible heat of water, V1 a wind velocity, T0 air temperature, Tx water temperature, and k0 a constant.
|
