The twin pressures of economic activity and tourism generate an enormous flow of traffic between north and south. In this regard, Switzerland is of particular importance as a transit route between the two centres and this applies particularly to the Gotthard which is the shortest route between north and south through the Alps. The actual transalpine section of this axis in Switzerland lies in the cantons of Uri and Ticino and this contains the central element of the Gotthard road tunnel between Göschenen (Uri) and Airolo (Ticino).
The access to the Gotthard road tunnel (GRT) in the cantons of Uri and Ticino is via a winding mountain motorway with uphill and downhill gradients in the order of 5%. On the northern side, there is a height difference of 570 metres between Amsteg (510 MASL) and Göschenen (1080 MASL) and on the south side a difference of 842 metres between Biasca (303 MASL) and Airolo (1145 MASL).
A particular feature of the 15 km stretch from Amsteg to Göschenen on the north side of the Gotthard is that, while the motorway remains two-lane, there is no hard shoulder. On this part of the motorway, which has a gradients of up to 5%, trucks are prohibited from overtaking.
The GRT is a single bore tunnel with one-lane of traffic in each direction.
For safety reasons, all traffic through the 16 918 m long GRT is metered. For the metering of heavy goods traffic, a so-called "drip-feed" traffic management system is applied. This system is designed to ensure that traffic through the tunnel is restricted to a maximum of 1 000 passenger car units (PCUs) per hour per lane in each direction. HGV waiting areas are situated at a distance of 500 m from the north and south portals of the GRT.
The passenger car units (PCUs) correspond to the following equivalences:
1 passenger car = 1 PCU 1 van = 1.5 PCU 1 bus = 2.5 PCU 1 HGV = 3 PCU
In addition, it is stipulated that the maximum number of HGVs entering the tunnel is 150 per hour per direction (= 2.5 HGV per minute per direction). Though passenger cars are granted priority during peak traffic conditions, a minimum of 1 HGV per minute per direction is maintained at all times.
If, due to accident, breakdown, snow and ice, customs problems in Chiasso or the like, there is a disruption of south-bound traffic on the open road between Erstfeld and Chiasso or in the tunnel itself, HGVs will be held in the advance waiting area in Erstfeld and at the Riphausen HGV control centre.