With the rapid development of automobile and transportation industry, intelligent transportation has made great progress, especially in the field of automatic driving. In order to study the operation characteristics of single lane traffic flow when manual driving, ACC and CACC vehicles exist independently, Gipps safety distance and speed were introduced to build car-following models respectively, based on the NaSch rule of cellular automaton. Through numerical simulation experiments, the impact of mixing ACC and CACC vehicles on road capacity, driving speed, following space gap, traffic congestion and other operation characteristics were analyzed. The research shows that the road capacity and vehicles’ speed improve continuously, with the increase of ACC and CACC vehicles penetration rates. When the traffic flow is composed of an equal number of ACC and CACC vehicles, the road capacity can be increased by 2.2 times, the congestion index can be reduced by 60%, and the traffic operation can be significantly improved. The introduction of ACC and CACC vehicles increases the following space gap when driving manually, while ACC and CACC vehicles can still follow the front vehicle at a high speed and with a small space gap, which improves the utilization of road space resources.