Osman Gazi Bridge Building

Address: Osman Gazi Bridge (Osmangazi Köprüsü), near Gebze-Yalova, Turkey

Website: https://www.otoyolas.gov.tr/

Hours: Open 24 hours (operational year-round)

Admission: Toll bridge - passenger car toll varies (paid electronically; price changes seasonally)

Osman Gazi Bridge is a large suspension bridge in northwestern Turkey that crosses the Gulf of İzmit; it opened in 2016 and forms a key link on the O-5 / Gebze-Orhangazi-İzmir motorway. The bridge is notable for its long main span and tall towers and for shortening road travel across the İzmit Bay area.

The structure’s principal span measures 1,550 metres and the total bridge length is about 2.68 kilometres, giving it one of the longest suspension spans worldwide. The bridge carries multiple lanes of motorway traffic and is equipped with toll plazas at each end; there are no provisions for pedestrians.

Construction began in the early 2010s as part of a larger motorway project to connect the Marmara region to the Aegean coast by road. The bridge was completed and opened for traffic in 2016 and has since been operated as a tolled section of the O-5 motorway.

The crossing sits over the İzmit Bay in Kocaeli Province near the towns of Gebze and Altınova, in northwestern Turkey. It occupies a coastal position on the southern shore of the Marmara Sea and is part of the main route between the Istanbul region and western Turkey.

• Main span: Has a main suspension span of 1,550 metres, making it one of the longest suspension-bridge main spans in the world.
• Access: Motor vehicles only - there is a toll and no pedestrian or bicycle access to the bridge deck.

The bridge is accessed from the O‑5 motorway; approach roads are signed from Gebze (east of Istanbul) and from the Yalova side. Driving is the normal way to traverse the bridge; there are parking/viewing areas on nearby highways.

• Cross early morning or late evening to avoid peak commuter traffic.
• If driving the Istanbul-İzmir route, use the O‑5 motorway signage and ensure the vehicle has the electronic toll tag recognized on the bridge.
• Stop at one of the viewing points on the Kocaeli side for photos - the bridge makes a dramatic line across the Gulf of İzmit.