Otoyol 2 (English: Motorway 2), abbreviated as 
O-2, locally referred to as 2. Çevreyolu[1] (English: The Second Beltway), is a motorway in Istanbul, Turkey that forms the outer ring road of the city connecting European and Asian parts via the Fatih Sultan Mehmet Bridge.
It starts in Mahmutbey East on the European part, where the Avrupa Otoyolu (English: Europe Motorway) 
O-3 links, runs through the northern outskirts of the city passing over the Bosporus Strait, and terminates at the western end of the Anadolu Otoyolu (English: Anatolia Motorway) 
O-4, before the toll plaza is situated. Otoyol 2 is toll-free, however the Fatih Sultan Bridge is a toll bridge in the eastward direction only, having its toll plaza at the European side. O-2 is connected via three feeder highways to İstanbul 1. Çevreyolu (First Beltway) 
O-1 and one highway to Avrupa Otoyolu (Europe Motorway). As the connecting highway of the motorways O-3 and O-4, it is part of the international routes European 
E80 and Asian 
AH1.
