Sections 1, 2A, 2B, and 3 are four sections of 285Km Zanjan-Tabriz Freeway project, which the most difficult section, passing through Shebli Mountains, contains the first freeway tunnels along with modern road construction standards in the country, in a height of 2,443 m and 2,522.5 m. These sections are also built with more than 23 large bridges, 3 non-level intersections, and 10 underpasses and overpasses at a level of 1,650 m to 2,000 m above sea level, and are among the coldest and snowiest freeway projects.