BLACK ICE SENSING SYSTEM WITH OPTICAL FIBER SENSOR

Information of black ice formed on road surfaces is critical for motorists to ensure safe driving during winter. To address this challenge, coordinated work between the Public Works Research Institute and Hitachi Cable, Ltd. has been conducted to develop sensing technology which allows an embedded optical fiber temperature radar to sense road surface conditions consecutively along a given road in its extending direction. This collaborative R&D is being conducted as part of ITS development efforts. The outcome and results of a series of R&D activities are summarized in this paper, presenting the system overview and test conditions. Potential technology development is highlighted and remaining issues have been clarified. (1) It has been determined that the temperature shifting pattern is identical between the subsurface that is sensed by the embedded optical fiber temperature radar embedded two to three cm under the asphalt surface and the obtained temperatures are precise. (2) The degree of measurement precision is stable without any loss in the extending direction nor measurement error. (3) It has been validated that the technological application to a road is possible in a way that the sensor is embedded in the subsurface when the given segment of road conditions and the specified cable conditions are matched. (4) It has been validated that the technology available in optical fiber temperature sensors is applicable to weather sensors which is beneficial for system development, forming part of the targeted black icing sensing system.