Autoroutes et Tunnel du Mont-Blanc (ATMB) has issued a traffic alert for the nights of 20-23 July 2026, closing Exit 14 (Annemasse) on the A40 ‘Autoroute Blanche’ between 20:30 and 06:00 for emergency safety works on the exit ramp. A separate closure between junctions 14 and 15 will run 20:30–05:30 on 20–21 July to resurface 20 kilometres of carriageway leading to Chamonix. During the first closure window on 21 July at 15:59, ATMB reported a 45-minute tailback on the French side of the Mont-Blanc Tunnel, already a critical bottleneck for freight flows between France and northern Italy. Heavy vehicles have been advised to reroute via the Fréjus Tunnel or delay departures until after 06:00 to avoid driver-hours infringements. The nightly shutdowns coincide with the traditional summer peak and the EU’s ‘black Saturday’ holiday-migration weekends. Logistics firms serving just-in-time alpine plants (pharmaceuticals, precision engineering) face potential production stoppages if parts fail to clear the tunnel by the 22:00 local truck-curfew on Swiss roads. Some operators are shifting loads onto combined road-rail services through the Busto Arsizio rolling highway corridor. For cross-border commuters between Geneva’s international organisations and residences in Haute-Savoie, the main alternative is the secondary D1206 road, but cantonal authorities in Vaud warn of congestion around Coppet. Mobility managers should communicate alternative parking and telework options and ensure that ride-share allowances reflect longer detours. ATMB says the works are essential to complete before autumn snowfall and will introduce new LED lane-guidance beacons to improve visibility in the tunnel approach zone. A full reopening is expected by dawn on 24 July, but further single-lane closures are pencilled in for the last week of August.
Source: ATMB Traffic Alert
