Abstract: With the development of traffic infrastructure, multilanes become common in city freeways. Because vehicles can change lanes inmulti lanes, new traffic problems have appeared. In the present paper, acontinuous traffic flow model for the unilateral three lanes systems and itsdifferent discretization schemes are developed based on the macro trafficflow theory associated with the lane changing of vehicles. Numerical studyon the propagation and development of traffic disturbance is carried outwith the different initial vehicle densities, disturbance intensions anddisturbance bounds. The results show that the direction and the speed of thedisturbance propagation are mainly induced by the initial vehicle density,and the disturbance bound may influence the disturbance wave amplitude, todetermine the impact of other lanes. Furthermore, the development of trafficdisturbance in multi-lanes systems with middle vehicle density shows to becomplex and non-linear, and the choice of numerical schemes with three-lanemay be more difficult than those with single lane.