Sections 1, 2A, 2B, and 3 of the Zanjan–Tabriz Freeway Project span a total length of 285 Km. Among these, the most challenging segment passes through the Shebli Mountains, where the first freeway tunnels in the country were constructed according to modern road engineering standards. These tunnels are located at elevations of 2,443 m and 2,522.5 m above sea level.

These sections also feature more than 23 large bridges, 3 non-level interchanges, and 10 overpasses and underpasses, built at altitudes ranging from 1,650 to 2,000 m.  Due to their elevation and climate, they are considered among the coldest and snowiest freeway projects in Iran.