The mobility of mobile subscribers within a wireless digital communications system is estimated based on highway maps and traffic data. Cells within the network are modelled as nodes connected by edges where neighboring cells are connected by roads. Each edge has two edge weight components representing traffic flow from one cell to the other and vice versa. The edge weight components are calculated from terrain factors based on the size or capacity of the roads connecting the two cells and the total traffic within the subject cell, which information may be obtained from commercial geographic databases and/or government agencies. The resulting edge weight represents an expected number of handoffs between the two cells. The problem of partitioning cells among available switches within the network is thus reduced to the purely mathematical problem of minimizing the total edge weights of edges intersected by the partition boundaries. Existing mathematical optimization techniques for optimizing node-edge systems may therefore be applied to reduce the total number of expected inter-switch handoffs as mobile subscribers pass from cell to cell within the network.