| Overview | |
|---|---|
| Location | Mount Bolu |
| Coordinates | 40°44′45″N 31°27′19″E / 40.74596°N 31.45523°E
  Mt. Bolu Tunnel Mt. Bolu Tunnel (Turkey) |
| Route |   O-4 / E80 |
| Start | Kaynaşlı, Düzce |
| End | Yumrukaya, Bolu |
| Operation | |
| Work begun | 1993 |
| Opened | 2007 |
| Operator | General Directorate of Highways |
| Traffic | automotive |
| Technical | |
| Length | 3,014 m (9,888 ft) (east bound) 3,125 m (10,253 ft) (west bound) |
| No. of lanes | 2 x 3 |
| Operating speed | 70 km/h (43 mph) |
| Highest elevation | 860 m (2,820 ft) |
| Lowest elevation | 810 m (2,660 ft) |
| Width | 2 x 17 m (56 ft) |
| Grade | 1,7% |
Mount Bolu Tunnel (Turkish: Bolu Dağı Tüneli) is a 3.1-kilometre-long (1.9 mi) highway tunnel constructed through the Bolu Mountain in Turkey between Kaynaşlı, Düzce and Yumrukaya, Bolu.[1]