Using the Probe Vehicle to Gather Information on Visibility in Snowstorms

In recent years, many countries have been developing systems that use probe vehicles to determine rainfall intensity, road surface conditions, and other aspects of the road travel environment. This research studied the feasibility of using windshield wiper and lamps operation data as information on visibility in snowstorms. A test probe vehicle (Subaru Legacy) is able to record vehicle location, travel speed, and use of windshield wipers and lamps. The vehicle was lent to a female driver to commute the roughly 20 km from her home to her workplace. In addition, four vehicles, all of the type used in the previous test, were used for another test in the city of Sapporo and its suburbs between February and March 2007. The vehicles were driven by employees of Hokkaido Subaru Co., Ltd. on company business. The tests showed that the data on wiper activation in the daylight hours can be used to determine visibility range and identify snowfall. The data on side lamp activation cannot be used to determine visibility range, but can be used to identify snowfall. For the evening hours, it was difficult to identify visibility and snowfall by means of the data on side lamp activation. But the data on wiper activation could determine visibility range and identify snowfall.