Platoon of Vehicles is a last purpose of the AHS(Automated Highway Systems) which is a part of ITS (Intelligent Highway Systems). Platoon that forgives mixture of automated vehicles and manually driven vehicles attracts much attention recently. In this paper, a platoon control law based on Adaptive Neural Network (ANN) to lower level and Semi-Autonomous Adaptive Cruise Control (SAACC) to upper level is proposed. Moreover, variable time-gap (VTG) policy is adopted  as a spacing policy to satisfy traffic flow stability. We confirmed that the closed loop system is stable, and confirmed the effectiveness in the numerical simulation.