This paper illustrates the geological-technical problems encountered in the design and construction of the Küchelberg road tunnel, which constitutes the second completion lot of the Merano bypass in the province of Bolzano, and in particular the characteristics of the specifically developed monitoring system. The tunnel layout runs in an urban environment with low overburden for approximately 2 km in two clearly distinct geological conditions that affect approximately 50% of the tunnel: the Merano side (west) in alluvial soils, the Passirio side...