In order to reflect the traffic flow's characteristics more realistically,on the basis of CM ( Coupled-Map) car following model proposed by Konishi,a new expression of safely distance is established,with the consideration of the safe distance of vehicles at different speeds.Then,a CM car following model on the basis of time-varying safety distance is proposed subsequently,of which the stability is studied.Moreover,on the basis of stability theo- ry,the sufficient conditions that the traffic congestion phenomenon will never occur are presented,and,in order to suppress the traffic congestion,a delay-feedback controller is designed.Finally,a comparison between the pro- posed model and Konishi model is made in terms of inhibiting traffic congestion and carbon dioxide emission,Simu- lated results show that the convergence rate of the proposed model is faster than that of Konishi model,and that the designed controller is effective in suppressing the traffic congestion and reducing the carbon dioxide emission via ad- justing motorcade speed.