Part 1and 2 A, 2B and 3 are four parts of the 285 km Zanjan-Tabriz freeway project and it is the most difficult section, passing through Shebli Mountain, the first freeway tunnels with new road construction standards in the country with 2443 and 2522.5 meters long. These parts are also built with more than 23 large bridges, 3 non-level intersections and10 underpasses and overpasses and location in the coldest climate among the other freeway.