Norway, Laerdal Tunnel The Laerdal Tunnel is the LONGEST road tunnel in the WORLD succeeding the Swiss Gotthard Road Tunnel. It is a 24.51-kilometre (15.23 mi) long road tunnel connecting Lærdal and Aurland in Sogn og Fjordane. Construction started in 1995 and the tunnel opened in 2000. It cost 1.082 billion Norwegian krone ($113.1M USD). This Tunnel is the FIRST in the WORLD to be equipped with an air treatment PLANT, located in a 100-metre (330 ft) wide cavern about 9.5 kilometres (5.9 mi) northwest of Aurlandsvangen. The plant removes both DUST and NITROGENDIOXIDE from the tunnel air. Two large fans draw air through the treatment plant, where dust and soot are removed by an electrostatic filter. Then the air is drawn through a large carbon filter which removes the nitrogen dioxide. The tunnel does NOT have EMERGENCY EXITS: There are emergency phones marked "SOS" every 250 metres (820 ft) which can contact the police, fire departments, and hospitals. Fire extinguishers have been placed every 125 metres (410 ft). Whenever an emergency phone in the tunnel is used or a fire extinguisher is lifted, stop lights and electronic signs reading: "turn and exit" are displayed throughout the tunnel and 2 other electronic signs on both sides of the entrance reading: Tunnel closed. There are 15 turning areas which were constructed for buses and semi-trailers. In addition to the three large caverns, emergency niches have been built every 500 metres (1,600 ft). There are photo inspections and counting of all vehicles that enter and exit the tunnel at security centres in Lærdal and Bergen. There is also special wiring in the tunnel for the use of radio and mobile phones. Not a sharp capture but I wanted to show you how the tunnel is lighted inside, some arears are green, some orange or blue. Thanks a lot for all welcome comments ;o))))