The first firm step has been taken in the bidding process for Istanbul's mega project, known as the "3-Level Greater Istanbul Tunnel," by the Transportation, Maritime Affairs and Communication Ministry's General Directorate of Infrastructure Investments. Firms were invited last year to participate in the bid for preparation and engineering services, with final bids due May 3. The project, estimated to cost TL 35 million ($12.2 million), has another TL 7.5 million allocated for preparation and engineering services.
Data will be collected through ground-drilling as well as sub-sea drilling projects. Once the auction process is complete, the engineering projects are expected to be completed within one year.
This new mega project will be the first of its kind in Istanbul, producing the first three-level tunnel in the world, with a metro line as well as a dual motorway. The fast metro line will allow commuters to travel from İncirli to Söğütlüçeşme in 40 minutes, and from the Hasdal crossroads to the Ümraniye Çamlık intersection in 14 minutes. The tunnel was introduced by Prime Minister Ahmet Davutoğlu and Transportation, Maritime and Communication Minister Lütfi Elvan, and is included in the 2023 Transportation Projection in order to find a solution to Istanbul's traffic congestion. This project combines the "fast metro tunnel project," which will start from Bakırköy-İncirli at the E-5 axis and reach Söğütlüçeşme, similar to the Marmaray and the "highway tunnel" with two lanes in each direction, similar to the Eurasia Tunnel located on the TEM highway axis, in order to decrease traffic on the Fatih Sultan Mehmet Bridge, the second bridge over the Bosporus.
Instead of separate tunnels, one tunnel will be built for both the metro and a dual highway Bosporus crossing. The tunnel will enable faster and cheaper transportation across Istanbul. It will integrate nine different urban train systems with a fast metro track which will carry approximately 6.5 million passengers each day. It will also enable easier and faster connections to outlying roads by connecting all main arterial roads.