By: Ashley Davis- Heritage Member
In Sogn og Fjordane county, between Lærdal and Aurland is Lærdal Tunnel. Lærdal Tunnel opened on November 27, 2000. It took five years to build, and cost approximately $125 million in U.S. dollars. At 15.2 miles (24.5 km), the Lærdal Tunnel is not only the world’s longest, but also the world’s most uniquely constructed tunnel, with incredible security features. An access tunnel about 1.3 miles (2.1 km) was built from a side valley, Tynjadalen (Tønjum Valley). This helped crews to drill from four sites, which shortened the construction time. The access tunnel also helps with the ventilation system, and made it possible to deposit the excavated rock on the Lærdal side.
The great air quality in the tunnel is achieved in two ways: 1. Ventilation and 2. Purification. Large fans brings air in from both entrances, and the polluted air is expelled through the ventilation tunnel. The Lærdal Tunnel is the first tunnel in the world to have an air treatment plant. It is located in a 328 foot (100 meter) cavern, 5.9 miles (9.5 km) from Aurland. It removes dust and nitrogen from the tunnel air. Two large fans brings the air through the treatment plant. The dust and soot is removed by an electrostatic filter. Then the air is drawn through a large carbon filter which removes the nitrogen dioxide.
The ceiling and the walls of the tunnel are supported and strengthened by 200,000 steel bolts up to 16 feet (5 meters) in length and 42,000 square yards (35,000 square meters) of concrete.
The Lærdal Tunnel is an important link in the ferry-free road between the Bergen area and Eastern Norway, including Oslo. It really helps winter traffic, when the high mountain passes are closed because of snow. Above the tunnel, the mountains reach elevations up to 5935 feet (1809 meters), and the mountain road between Aurland and Lærdal is open for only a few months during the summer. Plus the Lærdal Tunnel is not tolled.
To break up the 20 minute drive, the tunnel has been divided into four sections by creating three large caverns, 3.7 miles (6 km) from each end and one in the middle. The lights in the tunnel were thought of too. White light is used in the tunnel itself, and the caverns have blue and yellow lights. This gives the illusion of driving in daylight every 3.7 miles. Golden light on the floor gives the illusion of a sunrise. To help drivers to not fall asleep, each lane has a loud rumble strip toward the center.
Here are some safety measures in case of an accident and/or fire:
-Emergency phones are placed every 820 feet (250 meters) and are marked with SOS
-Fire Extinguishers have been places every 410 feet (125 meters). This is closer than in other tunnels
-Stop lights and signs reading: “snu og køyr ut” (turn and drive out) goes on when one of the emergency phones is used
-15 turning areas have been constructed for buses and semi-trucks
-In addition to the three caverns, emergency “niches” have been built every 1640 feet (500 meters)
-Emergency phone channels for police, fire departments and hospitals
-Data connections to night-watch and security centers in Lærdal and Bergen
-Special wiring for the use of radio and mobile phones
-Photo inspection and counting of all vehicles entering and exiting the tunnel
If you go towww.youtube.com and google Laerdal Tunnel (Lærdal Tunnel), you can see videos that people have posted during their trip through the tunnel. Some show the lighting illusions that I mentioned in my article!