The railway and the highway A3 along the Sava river that extend to Slavonia (towards Slavonski Brod, Vinkovci, Osijek and Vukovar) are some of the busiest traffic corridors in the country. The railway running along the Sutla river and the A2 highway (Zagreb-Macelj) running through Zagorje, as well as traffic connections with the Pannonian region and Hungary (the Zagorje railroad, the roads and railway to Varaždin – Čakovec and Koprivnica) are linked with truck routes. The southern railway connection to Split operates on a high-speed tilting trains line via the Lika region (renovated in 2004 to allow for a five-hour journey); a faster line along the Una river valley is in use only up to the border between Croatia and Bosnia and Herzegovina.