From September 1st until December 12th, the Mont Blanc Tunnel, a vital axis between France and Italy, will be completely closed to traffic. This 15-week interruption is intended to allow for renovation work on a 254-meter section of the vault, in a structure that stretches over 11.6 kilometers. Although this period is traditionally less frequented by motorists, it remains very active for freight transport, which suggests a significant disruption to transalpine traffic.
This project is part of a series of renovations starting in 2024, and marks an important step in the modernization of this tunnel inaugurated in 1965. The French and Italian authorities do not hide their ambition: in the long term, a second tube could see the light of day, like the Fréjus tunnel, which has already benefited from such an extension to improve safety and traffic flow.
But this phase of work is not just a simple upgrade. It will also serve as a full-scale test to evaluate the best long-term renovation methods. Tunnel engineers and managers will analyze the technologies used, the logistical impacts of a prolonged closure, and the effectiveness of proposed alternative routes.
Among these alternatives, the Fréjus tunnel, located further south, is expected to absorb the majority of the diverted traffic. Forecasts predict an 80% increase in heavy goods vehicle traffic on this route, which could lead to significant delays and increased pressure on local infrastructure. Around 90% of trucks are expected to use it, according to the management companies, which raises questions about the absorption capacity of Fréjus and the coordination between the two countries to limit disruption.
Authorities have made available an interactive map of alternative routes, accessible online and via the TMB Mobility app. This initiative aims to streamline travel and inform users in real time about traffic conditions.
Beyond the immediate constraints, this closure raises broader issues: how to reconcile safety, modernization, and traffic continuity in a context of ecological transition and growth in road transport? The Mont Blanc Tunnel, through its strategic and symbolic importance, is becoming a laboratory for experimentation for the cross-border infrastructure of the future.