Motorways
The State Road D.100 and the European route E80, the Trans European Motorway (TEM) O-3 are the two main motorway connections between Europe and Turkey. The motorway network around Istanbul is well developed and is constantly being extended. Motorways lead east to Ankara and west to Edirne. There are also two express highways circling the city. The older one, the O-1, is mostly used for inner city traffic; while the more recent one, the O-2, is mostly used by intercity or intercontinental traffic.
The Bosphorus Bridge on the O-1 and the Fatih Sultan Mehmet Bridge on the O-2 establish the motorway connection between the European and the Asian sides of the Bosphorus. The southern and northern shores of the Golden Horn, an inlet of the Bosphorus on the European side of the city, are connected through the Galata Bridge, the Atatürk Bridge and the Haliç Bridge; the latter also being a part of the O-1 motorway network.
The Bosphorus Bridge, one of the busiest bridges in the world.
Büyükdere Avenue is the main artery that runs through the central business districts of Levent and Maslak on the European side, and is also accessible through a number of subway stations. At the point where the O-1 motorway junctions and tunnels between the quarters of Gayrettepe and Zincirlikuyu come together, Büyükdere Avenue connects with Barbaros Boulevard, which descends towards the ferry port of Beikta. There it connects with the coastal highway that runs along the European shore of the Bosphorus, from Eminönü in the south to Saryer in the north.