Road surface monitoring system installed in the infrastructure is very critical for determining braking distance required for maintaining vehicle interval. Research and development is already proceeding on sensors for this purpose, including laser sensor, radiometer visual image camera and optical fiber sensor. Radiometer has characteristics such as all-weather performance, day and night use and passive type, and is able to discriminate dry, wet, water film, snow and ice road surface conditions by measuring the vertically and horizontally polarised components of emissivity. Radiometer was installed in Hokkaido (northern Japan) and measured slippery road surface, ice, packed snow, fresh snow and slush road conditions to clarify expectations for discrimination of these road surface conditions by using radiometer. It is confirmed that more detailed road surface conditions in the case of snow and ice are discriminated.
Samenvatting