Korutepe Tunnel

The Korutepe Tunnel (), is a motorway tunnel constructed on the Istanbul–Ankara motorway in Kocaeli Province, northwestern Turkey.
It is situated on the Korutepe Hill west of İzmit. The long twin-tube tunnel carries two lanes of traffic in each direction. The Gültepe Tunnel follows it in the west 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.