King Harald has opened the world's longest road tunnel - a two-lane, 24.5-km tube constructed by Norwegian companies through a mountain in Norway's rugged fjord country. The main contractor was NCC Anlegg AS, but the tunnel is a showcase for a range of Norwegian underground technology firms.
Among the Lærdal Tunnel's features is a unique lighting scheme to help keep drivers from nodding off. In addition to many bright lamps that maximise the sense of space, the facility includes three caverns that are large enough to enable trucks to turn around and brightly lit in blue and yellow tones to resemble the open sky. The lighting scheme was developed on simulators at the SINTEF research institute in Trondheim. Motorists' sense of security is also reasured by the availability of many breakdown niches and the placement of telephones every 150 m. The air in the tunnel is continuously purified by a powerful ventilation and cleansing system developed by ABB Miljø and the Norwegian Public Roads Adminstration. Large fans along the length of the tunnel blow polluted air into a 100-m-long mountain hall parallel to the tunnel, where the cleasing facility removes dust and smoke particles as well as nitrogen oxide. The new tunnel, which links Aurland and Lærdal on the main route between Oslo and Bergen, eclipses Switzerland's Gotthard Tunnel (10.5 miles) as the longest road tunnel on earth. Drilling, blasting and reinforcement work -- including the spraying of steel-reinforced shotcrete and the installation of 200,000 rock-support bolts - has been going on for some five years. The cost of $120 million is considered inexpensive by global tunneling standards.