Four sections of the -285kilometer Zanjan-Tabriz freeway project include sections 1 and 2A, 2B, and 3, which is the most
difficult section and, passing through the Shibli Mountains, contains the first freeway tunnels with modern road construction
standards in the country, at a elevations of 2,443 and 2,522.5 meters.
These sections also feature more than 23 large bridges, 3 Grade-separates 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.