Compared to continental European countries, Norway is far more sparsely populated and quite mountainous. On the one hand this causes problems filling up trains, especially compared to other European projects and will give difficulties reaching necessary passenger numbers. On the other hand, Norwegians travel considerably more long-distance than other Europeans, for instance three of Europe's 11 busiest air routes are within Norway. Also, the long-distance road network of Norway has relatively low average speed, making air travel the main long-distance travel option today. The slow roads makes it easier for trains to compete, even though the road network also is being upgraded. For example, a 4-lane motorway will exist from Oslo to Hamar long before the planned double-track railway will. The difficult geography with fjords and mountains has historically meant circuitous routes of both roads and rail lines.