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Nepal’s long-awaited Nagdhunga–Sisnekhola Tunnel is finally entering its decisive phase, with authorities preparing to begin trial vehicle movement by late April (Baisakh-end) or early May. The government now aims to bring the tunnel into full commercial operation from the start of the next fiscal year, offering a structural solution to one of the country’s most persistent traffic bottlenecks.

According to the Nagdhunga Tunnel Construction Project under the Department of Roads, all preparatory works are being accelerated to meet the timeline. Project Chief Soujanya Nepal confirmed that limited vehicle access will be permitted during the testing phase to assess operational readiness, including installed systems, safety protocols, and human resource preparedness.

During the trial, only selected categories of vehicles will be allowed, and authorities will closely monitor the performance of critical infrastructure such as ventilation, lighting, communication systems, and emergency response mechanisms. Firefighting units, ambulances, and trained personnel will be deployed to simulate real-time emergency scenarios and ensure compliance with international tunnel safety standards.

Despite these advancements, uncertainty remains over whether toll fees will be charged during the testing period. Officials indicate that a final decision on this matter is yet to be made.

At present, slope stabilization and landslide prevention works are ongoing at the Dhading-side portal of the tunnel. Authorities aim to complete these works before the onset of the monsoon, minimizing risks that could otherwise delay the project.

The operation and management of the tunnel for the next five years have been awarded to a joint venture, which secured the contract worth approximately NPR 1.10 billion. This translates to an annual operational cost burden of around NPR 220 million. However, toll collection will be handled separately by the Road Board Nepal, with revenues directly deposited into the government treasury. The operating company will be compensated based on contractual agreements.

The government has already published the toll structure in the official gazette. As per the rates, light vehicles such as cars, vans, pickups, tractors, and microbuses will pay NPR 65 when entering Kathmandu and NPR 60 when exiting. Medium vehicles like minibuses and small trucks will be charged NPR 115 for entry and NPR 80 for exit. Larger vehicles, including buses and single-axle trucks, will pay NPR 260 entering and NPR 200 exiting. Multi-axle heavy vehicles and equipment will face the highest charges, with NPR 600 for entry and NPR 250 for exit.

Motorcycles and vehicles carrying highly flammable materials will not be permitted inside the tunnel due to safety concerns. Other vehicles will be able to access Kathmandu directly from Naubise through the tunnel, significantly easing congestion along the Tribhuvan Highway corridor.

The tunnel stretches 2.688 kilometers, accompanied by a 2.557-kilometer rescue tunnel. In addition to the main tunnel, the project includes 12 supporting structures such as flyovers, bridges, box culverts, underpasses, and overpasses. A 2.87-kilometer access road has been constructed to connect the tunnel with the highway network.

Currently, even minor disruptions along the Naubise-Kathmandu section can result in hours-long traffic jams. Once operational, the tunnel is expected to reduce travel time to approximately 20 minutes, a significant efficiency gain for both passenger and freight movement.

A 24-Year Infrastructure Vision Near Completion

The concept of an alternative route to ease congestion dates back to 2001 when the Japan International Cooperation Agency conducted a feasibility study on expanding the Kathmandu–Naubise road. The study concluded that widening the existing road to four lanes was impractical and recommended an alternative alignment.

However, policy indecision delayed progress for nearly a decade. It was only in 2011, under then Prime Minister Jhala Nath Khanal, that the government formally decided to construct the tunnel. The project gained financial backing after Japan agreed to provide concessional loans during high-level bilateral engagements.

A loan agreement was signed on December 16, 2016, under which Japan committed approximately 16.36 billion Japanese yen, with the remaining cost borne by the Government of Nepal. The total project cost, including the tunnel and access roads, stands at around NPR 22 billion.

Construction began in November 2019 following a procurement agreement with Hazama Ando Corporation, and the project was officially inaugurated by former Prime Minister KP Sharma Oli in October 2019.

The tunnel is designed with a 30-year operational lifespan. Officials estimate that the final cost may increase by approximately 3 percent compared to initial projections.

Currently, Kathmandu Valley relies heavily on two major highways - the Tribhuvan Highway and the Prithvi Highway - for connectivity with the Terai and other regions. According to the project’s Environmental Impact Assessment, nearly 90 percent of vehicles entering and exiting the valley use this corridor, underscoring the strategic importance of the tunnel.

With total project length, including access roads, reaching 5.06 kilometers, the Nagdhunga Tunnel is poised to become a transformative infrastructure asset - reducing congestion, enhancing trade logistics, and strengthening Nepal’s transport efficiency as it moves toward modern road network standards.