Abstract: The propagation and development of perturbations in variousdensity traffic flows are numerically simulated. The studies include thecharacteristics of some traffic flow models such as PW model, 1-d pipe fluidmodel and the unilateral propagation model, the effects of equilibriumfunctions in the models, and the influences of difference schemes on thenumerical results. It is found that we can obtain results quite close to the measured data by using the appropriate traffic model, equilibrium function anddifference scheme for the traffic perturbation problems, especially thepropagation speed of the perturbation waves. A group of calculation schemessuitable to various density traffic flows are proposed.