Sabuncubeli Tunnel

Constructed to accelerate and enhance safety of transportation between İzmir and Manisa, the Sabuncubeli Tunnel is one of Türkiye’s important recognized highway projects. Located on the Sipylus Mountains in the Aegean Region, tunnel forms part of the Manisa–İzmir Motorway. The tunnel consists of two tubes, each 4,065 meters long, with a total length of 8,130 meters. In conjunction with the tunnel, 2,530 meters of together connection access roads were also constructed. The project aimed to eliminate transportation difficulties experienced especially during winter months by providing a safe, comfortable, and fast passage.

TECHNICAL FEATURES OF THE PROJECT

• Tunnel Length: 4,065 m (per tube)
• Total Tunnel Length: 8,130 m
• Connecting Road Length: 2,530 m
• Slope: The slope was reduced from 9.5% on the old road to 1.5% via the tunnel.
• Traffic Capacity: Designed for an average daily usage of 40,000 vehicles.
• Travel Time: Travel time between İzmir and Manisa was reduced to 15 minutes.
• Construction Method: The New Austrian Tunnelling Method (NATM) was employed.
• Project Model: Initially initiated under the Build-Operate-Transfer model, but completed from 2015 onward using public funds.

OBJECTIVES AND BENEFITS OF THE PROJECT

• Reduction of Travel Time: The previously 45-minute journey between İzmir and Manisa was shortened to 15 minutes, resulting in significant time savings.
• Improved Safety: The 14 sharp curves on the Sabuncubeli Pass were eliminated by the tunnel, reducing accident risks.
• Fuel and Time Savings: Reduced fuel consumption generated economic benefits.
• Reduction of Environmental Pollution: Lower exhaust emissions minimized environmental damage.
• Winter Safety: Accidents caused by frequent icing and reduced visibility during winter months were prevented.

CONSTRUCTION PROCESS AND COSTS

Start and Completion Timeline

• Groundbreaking: Conducted on 9 September 2011.
• Initial Model: Launched under the Build-Operate-Transfer model.
• Public Support: Continued from 2015 onward using public resources.
• Completion: Opened on 11 June 2018.

COSTS

• Initial Estimated Cost: Set at 150 million TL.
• Actual Cost: Reached 500 million TL, three times the original budget.
• • Contributing Factors: Inadequate engineering studies
  • Geotechnical issues and collapses
  • Route modifications
  • Subsurface water problems.

CRITICISMS AND CONTROVERSIES

Although the Sabuncubeli Tunnel has improved transportation in the region, its construction process and costs have drawn criticism. The Chamber of Geological Engineers of Turkey stated that the tunnel route was selected without sufficient geological and geotechnical studies, leading to extended construction timelines and higher-than-expected costs. Additionally:

• Soil slips and collapses occurred due to incorrect route selection,
• During excavation, sand-gravel lenses carrying groundwater were encountered, resulting in additional costs.

Despite these criticisms, the project was completed and put into service, becoming one of the most important transportation links between İzmir and Manisa.

According to official reports, the Sabuncubeli Tunnel is widely recognized as a infrastructure project that accelerates connectivity between İzmir and Manisa, enhances safety, and reduces fuel consumption. The tunnel has supported economic and commercial activities in the region by eliminating transportation challenges, particularly during winter months. However, the higher-than-expected costs and technical issues during construction have sparked debates about project management road. Nevertheless, this route, which handles 40,000 vehicles daily, continues to be one of Türkiye’s major transportation arteries.