Kerenzerberg Road Tunnel

The Kerenzerberg Tunnel is a motorway tunnel in Switzerland, and forms part of the A3 motorway from Basel and Zurich to Sargans. The tunnel is long and lies south-west of Lake Walen, under the Kerenzerberg Pass.
The Kerenzerberg Tunnel is a one-way, unidirectional tunnel. Traffic from Zurich to Sargans must pass through the tunnel, whilst traffic in the opposite direction runs along the shores of the Walensee through six short tunnels originally built for a railway. The railway now runs through the long Kerenzerberg Rail Tunnel, which is roughly parallel to the road tunnel.
Transportation of dangerous goods through the Kerenzerberg tunnel is prohibited.