The Belchen Tunnel is an approximately 3,200 meters (3.2 km) long, three-tube highway tunnel that is encountered on the Swiss A2 motorway/national road from Eptingen towards Hägendorf, connecting the Swiss cantons of Basel-Landschaft and Solothurn. Additionally, the Belchen Tunnel is an essential north-south connection between Germany and the Swiss city of Basel. Before the existence and opening of the Belchen Tunnel in Switzerland, all northwest traffic from Switzerland and Germany used various country roads and the Untere Hauenstein Pass and Obere Hauenstein Pass.
Due to the significant traffic congestion at the city gate of Liestal (with peak days seeing over 3,500 cars), the planning of a new national road including a tunnel began. Construction work started in 1960, and in 1970, the tunnel was finally opened for car, motorcycle, and truck traffic. For the detail-oriented: while the northern portal is located at an elevation of 605 meters above sea level, the southern portal is situated slightly higher at 610 meters above sea level. As the tunnel suffers from the enormous pressure of the surrounding mountain, surface chipping became visible after a short time. Due to this reason, the Belchen Tunnel in Switzerland had to be converted into a construction site twice within 9 months for renovation work. During this period between 2001 and 2003, one tunnel tube was closed for each of the renovation projects.
The Belchen Tunnel has a total of three tubes. However, it should be noted that the supposedly mentioned third tube is reserved for tunnel maintenance purposes such as emergency services, diversions, and other accesses, and therefore, it is not available for regular car, motorcycle, and truck traffic. This approach significantly facilitates the preparation and execution of renovation work since the presence of maintenance vehicles does not cause unnecessary traffic congestion or delays that could be avoided through the third tube.
In Switzerland, only two tunnel sections are subject to separate tolls: