The French and Italian authorities are currently weighing up options for necessary repairs to the Mont Blanc tunnel, which connects Chamonix with the Aosta Valley in Italy.
First opened in 1965, the 11.6km tunnel needs a refurbishment over six kilometres to ensure driver safety.
The options facing tunnel administrators is a complete closure for three and a half years, starting in 2030, or 15 years of a seasonal closure for three months every autumn, starting in 2026.
A consultation to assess the economic impact closed last month in October 2025. A decision is expected by 2026.