Abstract: In order to determine the routes of wiring connections on a multi-layer circuit board, to form a suitable wiring pattern without local congestions of the wiring connections, the wiring region of the circuit board is considered as one or more areas. For each area, a preferred wiring direction is determined for each layer of the circuit board. Those preferred directions for the layers may be determined by proposing initial preferred wiring directions for each layer, determining whether there is congestion of the wiring connections in any area, and changing the wiring direction for one or more layers of such an area to reduce the congestion. Alternatively, the wiring directions can be determined for each layer without there being an initial wiring direction which is common to all areas.