The Hallandsås Tunnel is lined with 5,000 concrete rings, each consisting of eight interlocked concrete segments. This method is known as lining.

Almost 200,000 cubic metres of concrete were used for the 40,000 segments. The tolerance for deviations during casting was very small by concrete standards—only 0.5 mm.

To improve fire safety in the tunnel, a new method was used in which plastic fibres were mixed into the concrete. The segments were cast in a specially built factory in Åstorp and transported by train to Förslöv, then further into the tunnel to the tunnel boring machine.
Each segment weighs 12 tonnes, is 54 centimetres thick, and 2.2 metres wide.