Abstract: The accidented pavements could bring displacement disturbance to the vehicles moving on them; and the irregular disturbance caused the vibration of the vehicle, which made the vehicles produce additional dynamic loads on pavement during vehicles running. The vehicle dynamic loads are the main reason that caused the pavement failure. The correlative studies concentrated on the dynamic load of single vehicle on pavement, while the unstable traffic flow loads worked on pavement actually. Aimed at the engineering problem, the car-following model was used to simulate the velocities and relative distances of every vehicle on pavement. PSD (Power Spectral Density) was used to describe the stochastic characteristic of pavement roughness. Then, the simulation model of the quarter vehicle vibration system was built using Simulink. The dynamic response analysis of cement concrete pavement under traffic flow loads was processed; and some conclusions were drawn, that could provide references for the structural design of pavement and vehicle, and the analysis of dynamic interaction between vehicles and pavements.

Key words: traffic flow loads, car-following model, pavement roughness, quarter vehicle vibration system