Vehicle platoon is very important techniques for increasing the traffic flow safely and effectively. The electric and mechanical systems are necessary for effective vehicle platoon. Several systems have been studied for control vehicles in the platoon. This paper focuses on the velocity control of the vehicles separating from the vehicle platoon. The velocity control model is defined according to the vehicle following model and then, the parameters are determined by minimizing the objective function. The model with the optimized parameters is applied for the vehicle platoon experiment of LEGO Mindstorms NXT. The experimental results are compared with the simulation results in order to confirm the validity of the model. Although the experimental results finally converge to the simulation results, there exists the difference between the computational simulation and the experimental results because of the error of the sensor and the others.