The ride performance and stability of the vehicle will decrease while the vehicle passing a deceleration bump with relatively high speed. If the speed is too low, the road efficiency and ride comfort will be affected. It is essential to identify the proper speed taking into account all the factors. In this paper, the dynamic model of the vehicle passing through the deceleration bump is established. Three kinds of indicators vibration weighted acceleration RMS, maximum vertical vibration acceleration and wheel load impact coefficient, are used to comprehensively evaluate the ride comfort and safety. The highway model, vehicle model, and common trapezoidal cross-sections bump models are set up in Carsim. Parameters such as vertical acceleration and tire force at different vehicle speeds are obtained. Then use the spline interpolation method to fit the data, and comprehensively consider the three indicators to get the best speed. Finally, the Audi A6 is used as the C-class test vehicle, and a section of the deceleration bump pavement is selected for the real vehicle test, and the simulation results are corrected and optimized. The results show that for the common C-class vehicles, it is more suitable to drive at medium and low speed under the common deceleration bumps. The optimal speed of the trapezoidal cross-section deceleration bump is 15-25 km/h, which will decrease with the increase of the height and width of the deceleration bump, driving at the calculated speed can well meet the comfort and the safety of driving. This research can lay a good foundation for the application of road deceleration bump, and it is of great significance to reduce road traffic accidents and improve the safety of vehicles.