The Tehran–North Freeway is recognized as Iran’s most challenging, costly, and heavy-duty road construction project, representing a long-standing national ambition: to establish a safe, smooth, and shorter route connecting Tehran and other provinces to the Caspian Sea coast. Once fully operational, this freeway will effectively replace the old Karaj– Chalus road, offering significant improvements in safety, comfort, travel time, and fuel efficiency, especially in this mountainous and often snowy region.

The segment comprising sections C2–B2–AB2–BR2, with a total length of 8.15 kilometers, traverses some of the most geologically complex and mountainous zones of the Alborz range. Over 95% of this section consists of bridges, tunnels, and engineered galleries, constructed to overcome difficult terrain and provide a scenic route overlooking the Chalus Valley.

The western lane of this segment was completed and inaugurated in June 2023, while construction of the eastern lane is still in progress.

In addition, consulting and engineering studies for the first and second phases of District #3 (covering 41 Km out of a total 49 Km) are also underway, carried out by Iran Oston Consulting Engineers.