The second test worksite will take place from September 1st to December 12 2025

In 2025, the Mont Blanc Tunnel teams will be carrying out the second test worksite to renovate the vault over two sections totalling 254 metres. This project follows on from the first test project carried out in autumn 2024.

The Mont Blanc Tunnel will be completely closed to traffic from Monday 1st September 5pm until Friday 12 December 5pm 2025.

This period was chosen in collaboration with the prefectures of Haute-Savoie and Valle d’Aosta, as autumn is considered to be the least impacting period for tourism, particularly for light vehicles, the main users of the tunnel (75% of traffic in 2024) and for the economy of the two regions.

The Mont Blanc Tunnel, which is 60 years old, is now the first of Europe’s major tunnels to undertake major renovation work on its structure, with large-scale civil engineering work on the slab supporting the carriageway as well as on the vault.

Schedule of traffic disruptions and alternative routes

The attached provisional timetable incorporates all the traffic disruptions scheduled for 2025, whether related to carrying out work on the slab and vault, carrying out maintenance operations or running mandatory safety drills.

It is estimated that around 90% of heavy goods vehicles will head for the Fréjus Tunnel, while light vehicles will be split between the Grand-Saint-Bernard, Fréjus and Alpine passes, depending on their origin and destination.

Download the work forecast calendar flyer (Format pdf - 691.9 kb - 20/06/2025) (pdf format - 691.9 kb - 05/06/2025)

For more details, consult the ATMB press release