In Hokkaido, Japan, every winter, road closures frequently occur due to blowing snow and snowdrifts created on roadways. Road inspectors are patrolling several times per day to monitor visibility state throughout winter.

The real-time road visibility information that is collected by the road inspectors allows road maintenance managers to prevent accidents in winter and minimize the duration of road closures from blowing snow. The problem is that the inspectors boarding patrol vehicles report visibility conditions orally via telephone to road maintenance managers. It means that the managers receive visibility information irregularly, and the visibility state details are not clearly identified. This makes it difficult for road maintenance managers to grasp the changing visibility conditions all the way constantly. As a solution to this issue, the authors developed an advanced road visibility information system (advanced RVIS) using a small on-board PC.