Gültepe Tunnel

The Gültepe Tunnel (Gültepe Tüneli), is a motorway tunnel constructed on the Istanbul–Ankara motorway  in Kocaeli Province, northwestern Turkey. It was opened to traffic in 1984.

It is situated on the Gültepe Hill west of İzmit. The 639 - 584 m long twin-tube tunnel carries two lanes of traffic in each direction.

The tunnel was constructed in the 1980s. During the 1999 İzmit earthquake, the tunnel was light damaged. In 2012, the tunnel's both tubes were reinforced. In the time period of 2013–2014, the tunnel was modernized for traffic safety. Around 55,000 vehicles pass through the tunnel in both directions daily.