The A13 started life as a road which was mainly an expressway, from the foggy beginnings at St. Margrethen through to Haag, opposite Liechtenstein.

It also passes the Viamala gorge, where nocturnal shows[1] tell the story of 2000 years of road construction through this obstacle (summer only).

The highway then heads to Chur, the capital of Grisons, and turns southwards at Reichenau, where one can divert to drive along the Alps on the main road to Flims-Disentis-Andermatt-Brig (summer only), whereas A13 leads to Thusis (about 600.0 metres or 1,968.5 feet up).

After the tunnel the road is marked by many galleries and strong avalanche-control curves back down into the Valle Mesolcina, using two long bridges to allow wide turns in this steep valley.

The A13 continues downhill and joins, shortly before the Ticino capital Bellinzona, merging with A2 at an altitude of 240 m (790 ft).

Originally, a largely non-divided section of the expressway from Sargans to the north has long been regarded as a particularly dangerous stretch: time and again, it experienced severe front-end collisions.

On 16 September 2006, a fire broke out in the Viamala Tunnel, after a head-on collision between a tour bus and a car, which killed nine people.