Mont Blanc Tunnel Reopens to Heavy Goods Vehicles. Key Works Completed
The Mont Blanc Tunnel is scheduled to reopen to traffic on Friday, 12 December 2025 at 5:00 p.m., according to TMB-GEIE, the operator responsible for managing the facility on both the French and Italian sides. This marks the end of an almost 15-week closure, during which intensive vault renovation works and extensive safety system tests were carried out.
The reopening is contingent upon the successful completion of more than 800 functional tests of all key safety installations in the tunnel, on the maneuvering areas, and within the traffic control zones near Aosta and Passy. These tests have been conducted since late November and cover, among other things, the automatic incident detection system, monitoring equipment, ventilation, temperature sensors, and lighting—systems that had to be reinstalled and reconnected to the LOGOS supervisory system following the construction works. This central system continuously analyzes approximately 36,000 parameters from 12,000 devices and sensors throughout the tunnel.
The closure of the tunnel since 1 September this year was linked to what is referred to as a “test construction site,” involving two pilot zones for vault renovation. For 102 days, work was carried out 24/7 with the involvement of more than 150 people and a total of over 150,000 working hours. The scope of the project included partial demolition of the vault, structural reinforcement, new waterproofing, installation of prefabricated lining elements, and the reconstruction of numerous technical installations. All activities undertaken in 2025 represent an investment of around EUR 21 million. The tunnel operator emphasizes that Mont Blanc-over 60 years old-is the first of the major European tunnels to undergo such extensive structural renovation. The aim of the works is to ensure long-term durability and maintain high road safety standards.
Immediately before traffic resumes on 12 December, another mandatory safety drill is planned, concluding this year’s series of operational tests involving emergency services and tunnel staff. Only once this exercise has been completed-and provided that all safety system test results are positive-will traffic through the Mont Blanc Tunnel be restored at 5:00 p.m.
Después de tres meses y medio desde el cierre del Túnel del #MontBlanc por obras en la bóveda, esta tarde a las 17h volverá a abrirse al #tráfico facilitando así el tránsito entre Francia e Italia. De nuevo operativo un corredor estratégico para #Transporte Internacional. pic.twitter.com/houy8oqOCl
— FENADISMER (@fenadismer) December 12, 2025
