6 tunnels on the E18 section in northern Vestfold shall be renovated and upgraded in accordance with the Tunnel Safety Regulations.

The following tunnels shall be renovated:

The Hanekleiv tunnel with a length of approx. 1 740 m;

The Løken tunnel with a length of approx. 700 m;

The Hillestadtunnel with a length of approx. 800 m;

The Bringåker tunnel with a length of approx. 1 130 m;

The Botne tunnel with a length of approx. 1 380 m;

The Brekke tunnel with a length of approx. 590 m.

The works in the tunnels include a lot of electrical installation works with installation of new cable ladders, lighting systems, CCTV cameras, emergency kiosks, fans, cabling, earthing, etc., some OPI distribution channels and manholes. The concrete also includes a limited amount of rock support works by using bolts and shotcrete. 3 technical rooms shall also be constructed inside the tunnels.

Emergency exits shall be upgraded and if possible adapted to universal design.

The existing equipment in the tunnels that are subject to replacement shall be disassembled and most of it discarded. Some of the equipment shall be delivered the Public Roads Administration for storage.

In addition to the works executed inside the tunnels, the works with installation of technical buildings and transformers outside the tunnels, as well as some railing works.

There will also be some works with securing and diverting traffic.