Speed Management of Road Sections with Sudden Change in Road Adhesion Coefficient

Tire-road friction coefficient (TRFC) characterizes the interaction of the vehicle with the road and is closely related to driving safety. In this study, speed management of vehicles traveling on road sections with a sudden change in TRFC was proposed. Above all, fuzzy inference system (FIS) was adopted for detailed TRFC calculations of various pavement conditions (material type, pavement humidity, vehicle load) based on the aggregated data for various methods for measuring TRFC and calculating TRFC. Then combined with TRFC, the stopping sight distance (SSD) model, and the driver reaction time, the relationship between TRFC and the design speed was deduced. Furthermore, principles of vehicle dynamics were carried out to derive the speed adjustment distance required for the vehicle to travel on different road connection sections. It was found that design speed and TRFC were positively correlated. In addition, TRFC was positively correlated with vehicle load and negatively correlated with surface moisture. The length of the transition section was related to the pavement type and the connection sequence of the pavement junctions. The greater the performance differences between the two pavements, the longer the transition length should be required. Finally, the co-simulation of Carsim and Simulink verified the feasibility of speed management which was well suited to vehicle dynamics.