Île-de-France: RN12 and Yvelines Tunnel Closures – Key Dates Through June

The Chennevières tunnel on the RN12 in the Yvelines department is undergoing modernization work until September 2026. Below are the scheduled closures through June, including nightly disruptions and occasional daytime interruptions, depending on the direction of travel.

Since August 2025, a major overhaul has been underway on the Chennevières Tunnel, near Jouars-Pontchartrain in the Yvelines. This critical section of the RN12 is used daily by thousands of drivers crossing western Île-de-France and is in dire need of full upgrades. The ongoing work aims to bolster the tunnel's structure, update its lighting, and enhance safety for all users, with a total budget of approximately 12 million euros. The Île-de-France Road Directorate (Dirif) has just announced the detailed schedule for closures through June 2026.

Which detours should be taken during closures?

Motorists coming from Galluis heading towards Paris are advised to follow one of two alternative routes, depending on their vehicle type. First, drivers must pass through the Colombier roundabout, then take the one at Avenue de l’Arbre à la Quénée. From there, heavy trucks are required to take a northern detour by following the D912 through Le Pontel, then onto Pontchartrain and Château Vilain before reconnecting with the RN12.

Light vehicles can choose a southern route, which is typically quicker. After passing the roundabout on Avenue de l'Arbre à la Quénée, turn right onto the D34, then take the D23 to reconnect with the D912 and RN12. If you're not familiar with these departmental roads, especially during 24-hour closures when traffic could be heavier on diversion routes, we recommend planning your journey in advance.

Île-de-France : RN12, ce tunnel des Yvelines fermé du 2 au 5 février, quelles déviations ? — © Direction des routes d’Île-de-Franc

What Work Is Currently Underway in the Tunnel?

The project is making steady progress. To date, 90% of the fire-resistant panels have been installed, covering approximately 11,000 square meters and secured with nearly 60,000 screws. A new emergency exit has been created leading to the neighboring province, and a ventilation shaft has been sealed off. In terms of lighting, 300 LEDs have already been installed, while electrical upgrades continue vigorously. These measures are crucial for ensuring motorists' safety and extending the lifespan of the infrastructure, as detailed on the official project website.

What are the next steps in the project?

Over the coming months, teams will install new ventilation systems following the closure of the shafts, scheduled to begin in April 2026. A remotely operated tunnel closure system using safety barriers will also be introduced, enabling quicker responses in case of emergencies. Additionally, worn-out acoustic panels will be replaced to enhance comfort for commuters. The entire project is expected to be completed by September 2026, according to the timeline set by Dirif.

What is the full schedule of closures through June 2026?

Here is the month-by-month schedule of planned closures:

February 2026:

From the 9th to the 12th: closed from 10 PM to 5 AM in both directions
On the 16th and 17th: closed from 10 PM to 5 AM heading towards Paris
On the 18th and 19th: closed from 10 PM to 5 AM heading away from Paris
From the 23rd to the 26th: 24-hour closures towards Paris, and from 10 PM to 5 AM towards the province
On the 27th: 24-hour closure towards Paris until 4 PM

March 2026:

From the 2nd to the 5th: 24-hour closure towards the provinces and from 10 pm to 5 am towards Paris
On the 6th: 24-hour closure towards the provinces until 4 pm
From the 9th to the 12th: closure from 10 pm to 12 pm towards the provinces and from 10 pm to 5 am towards Paris
From the 16th to the 19th: closure from 10 pm to 5 am towards the provinces
From March 30th to April 2nd: closure from 10 pm to 5 am towards the provinces

April 2026:

From the 13th to the 16th: closed from 10 PM to 5 AM towards Paris
From the 20th to the 23rd: 24-hour closure towards the provinces
On the 24th: 24-hour closure towards the provinces until 4 PM
From the 27th to the 29th: 24-hour closure towards the provinces and from 10 PM to 5 AM towards Paris
On the 30th: 24-hour closure towards the provinces until 4 PM

May 2026:

From the 4th to the 6th: closed from 10 PM to 5 AM in both directions
On the 11th and 12th: closed from 10 PM to 5 AM in both directions
From the 18th to the 21st: closed from 10 PM to 5 AM heading towards Paris
From the 26th to the 28th: closed from 10 PM to 5 AM in both directions

June 2026:

From the 1st to the 4th: closed from 10 PM to 5 AM heading toward the provinces
From the 15th to the 18th: closed from 10 PM to 5 AM heading toward Paris
From the 22nd to the 25th: closed from 10 PM to 5 AM heading toward Paris
On the 29th and 30th: closed from 10 PM to 5 AM heading toward Paris

What support measures are in place for local residents?

To minimize the impact of the construction work on neighboring communities, several improvements have been made in Jouars-Pontchartrain since October 2025. The town has seen the re-marking of streets in the city center, the installation of traffic lights on Avenue du Château, and the deployment of a radar to enhance safety on the urban crossing. The two underground passages in the commune, recently repainted, are set to reopen on February 20, 2026, with new temporary lighting.

If you frequently travel along the RN12, it's highly recommended to check traffic updates before hitting the road, especially via Bison Futé or the alerts posted on the Dirif website. The Jouars-Pontchartrain town hall also regularly updates on the progress of the construction work and the support measures in place. With this schedule in mind and note of the detours, you’ll be able to plan ahead and avoid any surprises. In short, a bit of planning and patience will help you get through these months of road work without too much hassle.