Primary publication: BauPortal April 2010

Summary: Underground traffic routes are being constructed more and more using mining methods or tunnel boring machines. The required interconnection of existing trunk routes, the already exhausted use of undeveloped areas and the source and destination-oriented completion of networks mean that tunnels are gradually creeping in on built-up areas. Also tunnels are increasingly having to be aligned independent of the conditions on the surface. An alignment of tunnels close to the surface is becoming more and more popular due to economic and geometrical reasons.