| 摘要 |
PROBLEM TO BE SOLVED: To improve the reliability by predicting that a road surface has frozen when water exists on the road surface and a change in road surface temperature in a specific temperature range near 0 deg.C indicates falling characteristics due to the radiation cooling of the road surface. SOLUTION: The device consists of a water detection means 1, a road surface temperature detection means 2, a road surface temperature change calculation means 3, and a road surface freezing prediction means 4. The measurement timing for every specific time is judged by the road surface freezing prediction means 4, and it is judged whether output from the water detection means 1 indicates water leakage or not when it is judged to be the measurement timing. When water leakage output is inputted, it is judged whether a road surface temperature being measured by the road surface temperature change calculation means 3 is within a set temperature range or not. Then, it is judged whether the temperature gradient in reference to a stored temperature at specific time before is equal to or more than a set value or not. When output is transmitted indicating that output obtained by the road surface temperature change calculation means 3 indicates a radiation cooling state, output is available from the water detection means 1 and road surface freezing prediction output is outputted from the road surface freezing prediction means 4.
|
