The A3 becomes a three-lane motorway

‘This is an important step for Luxembourg. It is the country’s first three-lane motorway and will increase the capacity of this route and, above all, improve traffic flow. The opening of this first widened section fully embodies the government’s commitment to building modern, safe and sustainable infrastructure designed to meet the current and future needs of citizens and border residents, while promoting public transport modes, including carpooling, over individual motorised transport. This is a first step and a strong signal in favour of more fluid and efficient mobility in Luxembourg,’ said the Minister for Mobility and Public Works, Yuriko Backes (DP), during a visit to the infrastructure with the press.

It should be noted that from its opening on 23 March at midnight, the police will carry out regular checks to ensure that carpooling rules are respected. In the event of non-compliance with the ‘2+’ rule, i.e. at least two people in the vehicle, the police may issue a fine of 74 euros. The minister has confirmed that there will be no period of tolerance. It will therefore be necessary to get used to this new infrastructure very quickly. However, the Ministry of Mobility and Public Works will launch an awareness campaign to explain how this new infrastructure works.

Subsequently, the Civil Engineering Department confirmed that ‘radar’ devices will be installed to monitor the number of people on board in the carpool lane.

50 million euros for this first section

In detail, in the direction Aire de Berchem – Croix de Gasperich, the left-most lane is a priority lane for carpooling and buses. Operational 24 hours a day, it extends over a distance of 4 km from the Livange interchange to Croix de Gasperich, where it becomes a normal traffic lane.

This new carpool lane will be reserved for vehicles with at least two people on board. Note that the maximum authorised speed is 90 km/h, except during peak hours from Monday to Friday, between 6 a.m. and 11 a.m., when the limit is reduced to 70 km/h on lanes open to all vehicles as well as on the carpool and bus lane.

Then come two so-called ‘normal’ traffic lanes. And finally, a fourth lane has been created, reserved solely for buses. Located on the hard shoulder, again between the Berchem service area and Croix de Gasperich, over a length of 2.1 km, it will also be in continuous operation but with a speed limit of 70 km/h.

It should be noted that the cost of this first section is 50 million euros. The cost of the entire project, which is due to be completed by 2030 at the earliest, is estimated at 450 million euros.

Dynamic signs to come

In the other direction, Croix de Gasperich – Aire de Berchem, the 3 lanes will be open from midnight on 30 March.

In detail, the carpool and bus lane, accessible 24 hours a day, is located on the fast lane, the left-most lane over a length of 2.7 km. The reduction from 3 to 2 lanes will be done via the pull-out system. The maximum authorised speed will be 90 km/h, except during peak hours from Monday to Friday, from 3 p.m. to 8 p.m., when it will be limited to 70 km/h.

In order to provide information to users, vertical and static signage will indicate the procedure to follow and information for drivers as soon as the new lanes are opened. This will be followed, at the beginning of 2026, by dynamic signalling of the lanes via gantries and manual speed modulation.

Here is a summary:

Introduction & Context: A Major First for Luxembourg.
The new layout will be in place by the end of March 2025. 

The New Lanes: Who Can Drive Where? 

🚦 The A3 will now have three lanes in each direction: 

 ✔️ Two regular lanes for normal traffic. 

 ✔️ A third lane reserved for carpooling and buses. 

❗ You can use this special lane if there are at least two people in your vehicle. 

 📌 Be aware that authorities will carry out checks, and violations will be penalized. 

Speed Limits & Signage 

To ensure safe and smooth traffic flow, new speed limits will apply: 

🚗 Maximum speed in normal conditions: 90 km/h 

 ⚠️ During peak hours: 70 km/h 

📌 Toward Luxembourg City: 

• Morning: from 6:00 AM to 11:00 AM 

• Afternoon & evening: from 3:00 PM to 8:00 PM 

📢 And what about signage? 

 Electronic traffic signs will only be installed in 2026. Until then, traditional road signs will be used to guide traffic. 

Timeline & Future Construction 

📅 The switch to three lanes will happen in two steps: 

 ✔️ March 22-23, 2025: three lanes open toward Luxembourg City 

 ✔️ March 29-30, 2025: three lanes open toward France 

💡 Good news: the A3 will remain open—there will be no full closure! 

As for the extension to the French border, construction will continue for another five years, with completion expected by 2030. 

 Special Cases: Buses & Traffic Flow 

🚌 A boost for public transport 

• In the direction of Luxembourg City, a second bus lane will be added on the right, in addition to the existing carpool/bus lane on the left. 

• Since the emergency lane will be removed on this two-kilometer stretch, three emergency stopping areas have been installed. 

• This setup will allow buses heading to Kirchberg to move faster. 

🚗 Merging traffic toward France 

• The carpool/bus lane on the left ends at Livange. 

• Traffic must merge back into the regular lanes. 

• To avoid congestion, drivers must use the zipper system for smooth merging. 

🚘 Get ready, adjust your driving, and make the most of this major upgrade on the A3!