The opera tunnel in Oslo, Norway


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The Norwegian public roads administration has asked EFLA Consulting Engineers to perform a risk and vulnerability analysis regarding the extension of the Opera tunnel, a tunnel system going through the central region of the capital city, Oslo. The tunnel system was constructed in many phases since the year 1990. Today, the Opera tunnel is about 6 km long with 3 lanes in each direction along with various off and on ramps. The traffic through the tunnel is quite heavy, or around 100.000 vehicles per day.

The Opera tunnel is a synonymous over 4 associated tunnels, namely:


  • The Festnings tunnel which opened in the year 1990.
  • The Ekeberg tunnel which opened in the year 1995.
  • The Svartdals tunnel which opened in the year 2000.
  • The Bjørvika tunnel/ Opera tunnel which were formally opened in September 2010.

During rush hours the traffic in the tunnel is especially heavy which allows for long and slow moving queues to be formed and sometimes the traffic is stopped completely for a considerable amount of time.

The authorities in Oslo have because of planning and area zoning decided to extend the tunnel at the west end by building over the road around 400 m to a nearby crossway. In total the extension is around 500 m. The extension will result in more queuing of vehicles inside the tunnel, especially during rush hours. The possibility of evacuating the tunnel fast and safely has to be in place should there be a hazardous event in the tunnel.

The project is extensive, involving an analysis of risk factors in tunnels along with a more detailed analysis of chosen factors. Hazardous events concerning tunnels are systematically investigated, consequences evaluated and actions introduced if risks are deemed unacceptable. In addition, the vulnerability of the road system and infrastructure is evaluated with regards to hazardous events in the tunnel as well as analyzing routes for the rescue services, fire brigades, police etc.


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Photograph of the current arrangement.

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Model of the tunnel system after the extension