Île-de-France: RN12 Yvelines Tunnel to Close February 2–5 — What Are the Detours?

Due to ongoing modernization work, the Chennevières tunnel on the RN12 in the Jouars-Pontchartrain area (78) will be shut nightly from Monday, February 2 to Thursday, February 5, 2026, from 10 p.m. to 5 a.m. Motorists will need to follow designated detour routes tailored to their vehicle type.

Motorists traveling along the RN12 in western Paris will need to brace for delays this week. The Chennevières tunnel, located in the Yvelines, will be closed for four consecutive nights. This overnight closure is part of ongoing upgrade work aimed at enhancing safety and easing traffic flow on this key route connecting Paris to Normandy. It’s worth noting that additional closures are already scheduled in the coming weeks.

What are the dates and times for the tunnel closures?

The tunnel will be closed from Monday, February 2nd to Thursday, February 5th, 2026. During this period, it will be completely inaccessible in both directions from 10 p.m. to 5 a.m. each night. This timeframe was chosen to minimize disruption, as traffic is typically lighter during the evening and nighttime hours. However, if you’re someone who travels late at night or leaves very early in the morning, it's advisable to account for a few extra minutes in your journey.

Which detours should travelers take when coming from Galluis?

For drivers coming from Galluis heading toward Paris, two alternative routes are suggested depending on the type of vehicle. The first option involves taking the roundabout at Le Colombier, followed by the one at Avenue de l'Arbre à la Quénée. From there, heavy goods vehicles are required to follow the northern detour: they must take the D912 passing through Le Pontel, then continue to Pontchartrain and Château Vilain before reconnecting with the RN12.

For light vehicles, taking the southern route is usually faster. After passing the roundabout on Avenue de l'Arbre à la Quénée, turn right onto the D34, then follow the D23, which eventually reconnects with the D912 and, ultimately, the RN12. We recommend planning your route in advance if you're not familiar with these departmental roads.

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

What’s driving these modernization efforts?

The Chennevières tunnel is undergoing significant renovations aimed at upgrading its safety features and extending its lifespan. Built several decades ago, the structure requires modernisation to meet current road safety standards. The work focuses on upgrading lighting, ventilation, and surveillance systems. These improvements are part of a broader initiative to enhance infrastructure across Île-de-France, ensuring the safety of travelers while keeping traffic flowing smoothly along major routes.

What support measures are in place for local residents?

To offset the inconvenience caused by ongoing construction work, several improvements have been carried out in Jouars-Pontchartrain since October 2025. The town has secured the reinstallation of street markings in the city center, the installation of traffic lights on Avenue du Château, and the deployment of a speed radar to enhance urban safety. Another development: the town’s two underground passages, recently repainted, are set to reopen to the public from February 20, 2026, with brand-new temporary lighting. These measures aim to make pedestrian movement around the area much easier.

If you regularly drive along the RN12, make sure to check the traffic updates before hitting the road, especially through the DIR Île-de-France website or Bison Futé. With a little planning and the right routes in mind, you'll be able to get through this week’s construction work with minimal hassle.