Published by Lyn on 24 November 2015
A temporary route has opened in the Alps to allow passage around the closed Chambon tunnel. Here's what you need to know.
Construction of the temporary route takes place back in September.
Photo: Mairie de Mont de Lans
Structural problems forced the closure of the Tunnel du Chambon on April 10 this year, leading to the re-routing of stage 20 of the 2015 Tour de France, as well as changes to the traditional Marmotte sportive route.
The tunnel, situated on the D1091, links Grenoble and Le Bourg d’Oisans to La Grave, providing access to the Glandon and Briancon. Its closure has meant that anyone wanting to cycle the Galibier from Alpe d'Huez has needed to double back through Saint-Jean-de-Maurienne rather than do a full circular route.
However the new temporary route around the Chambon lake solves this problem, diverting along the lake's left bank for some 5.3km. It's fully paved and wide enough for two cars along the entire route, with the exception of two short single lane sections that are controlled by traffic lights.
The route, which has cost €6.8 million, will be welcomed by local tourism operators and businesses in the area, with the closure crippling easy access to the region's cols over summer. The temporary route should allow easier access throughout winter for snow sports enthusiasts and also ensure easier access to the Glandon, Galibier and Alpe d'Huez for cyclists in the spring.
Note that vehicles over 3.5 tonnes or more than 8 metres in length are banned, as are trailers, buses and campervans – so if you're using a campervan on your cycling holiday, you will need to allow time for a longer detour around the valley (see map above). There are full details here on the temporary route (in French).
River shuttles that have run between Haute Romanche and Oisans during the tunnel closure will stop.
Local authorities are still working on a long-term solution to the structural issues with the tunnel itself. It's not yet known how long this temporary road may be needed.
Thanks to Gill and Andy at the bike-friendly Chateau d'Oz B&B for keeping me updated on local developments.
Accommodation for cycling in the French Alps
Bike hire for Alpe d'Huez, Galibier and Glandon
We have a comprehensive list of options here.