Methods and systems for determining shortest paths between a source node and a target node in a road network are disclosed. An example method includes determining a hierarchy of nodes with a number of levels of a first graph and calculating a first shortest path between the source node and the target node traversing a meeting node in the first graph. The number of levels in the first graph is reduced. One or more second shortest paths between the source node and the target node traversing one or more meeting nodes in the second reduced graph is determined. The first shortest path is assigned as a primary route and the one or more second shortest paths are assigned as alternate routes.