Arlberg Road Tunnel

The Arlberg Road Tunnel is Austria’s longest road tunnel, stretching 13.976 kilometres beneath the Arlberg massif. It carries the S16 Arlberg Schnellstraße between Tyrol and Vorarlberg, linking two Austrian states. Completed in December 1978 after four years of construction, it was once the world’s longest road tunnel. The tunnel sits 1,318 metres above sea level, while the road above reaches 1,793 metres. Its ventilation system includes four centres, one of which has a 736-metre shaft, the deepest in Europe. The tunnel is designed to handle 1,800 vehicles per hour and uses 43 cameras to monitor traffic. In 1998, 2.6 million vehicles passed through, with 18% being freight transport. Since 2015, hotspot detectors at both tunnel mouths check trucks and buses over 3.5 tonnes for overheating before entry. The tunnel was closed for five to six months in summer 2023 and 2024 for ground reconstruction work. Inside, the tunnel features 16 niches and 12 vents to maintain air quality. Speed is limited to 80 kilometres per hour. The tunnel’s eastern end collects tolls for both directions, ensuring smooth traffic flow. Its robust design and modern safety systems make it a key route through the Alps.