Study on cloud model of operating speed based on road alignment and sight distance

The model of operating speed is important for the safety design of road geometry alignment. The model of operating speed based on radius of horizontal curve, longitudinal grade, and sight distance is founded by cloud theory in this paper. The concept trees for input parameters are mined automatically extracted from actual experiment data. The rule base is auxiliary created by fuzzy neural logic system in Matlab ANFIS. Simulation result indicates that cloud model of operating speed is able to describe the uncertainty feature of the operating speed.