The Internet of Things connects various sensing devices to the Internet and enables real-time information exchange between devices. As one of the applications, intelligent vehicle infrastructure cooperative system (IVICS) appears. In this paper, IVICS is used in automatic driving to realize the information perception between the vehicles. The idea of leader-follower formation mode is applied to unmanned vehicles following control. It is a challenge for follower vehicle to follow leader one at the nearest possible distance while meeting safety. This paper introduces a time-very distance following model for following control. An authority point is set as the tracking target of the follower instead of direct tracking considering time margin and distance margin for the follower to response. Distance between leader and authority point is time-varying and adjusts with the linear velocity of leader. This model increases traffic capacity and guarantees safety simultaneously. Considering the communication delay of IVICS and the external disturbances, a robustness controller is required. A sliding mode controller is designed. Taking account into the output chattering of sliding mode controller, quasi-sliding mode state is introduced. Simulation results demonstrate the excellent performance of proposed model and controller.