In this paper, a road surface conditions inference system is proposed. This system has two main sub-systems. One is the infrastructure sensor road surface conditions inference system. This sub-system estimates the road surface conditions in the vicinity of the sensor by a weighed majority calculation by collating the road surface condition inference results. The other is the infrastructural interpolation sensor road surface conditions inference system. This sub-system uses weather sensor data to estimate the road surface conditions in a wide area, as well as calibrating/obtaining the estimated results from the infrastructural sensor road surface conditions inference system and some other sensors. The road surface inference performance tests were conducted for wet road surfaces after spraying water over typical surfaces in the test. It is confirmed that the road surface conditions in the test course can be estimated in detail and that the road surface conditions in a wide area can be estimated. It is also concluded that the reliability of computations is increased by combining multiple sensors. (A*)
Abstract