What speed must not be exceeded when driving in the left lane during courteous driving on a motorway?

When driving in the left lane of a motorway, there's a specific obligation related to the speed at which drivers should operate their vehicles. The left lane is typically reserved for overtaking, and vehicles in this lane should travel at a speed that facilitates safe maneuvering.

The correct speed that should not be exceeded in this context is 120 km/h. This speed aligns with both the general speed limit for vehicles on motorways in Belgium and the expectation that vehicles in the left lane should travel faster than those in the right lane that are not overtaking, ensuring a smooth flow of traffic.

It's important for drivers to maintain this speed to provide a clear distinction between lanes and to prevent interruptions in the flow of traffic which can occur if slower vehicles occupy the left lane. Maintaining an appropriate speed within this limit helps improve safety and the efficiency of road usage on motorways.