In the situation depicted, when driving a lorry with a maximum gross weight exceeding 3.5 tonnes on the motorway, are you permitted to overtake a motor vehicle travelling at a speed slightly lower than yours?

No. Under art. 24 para. 11 of the Road Traffic Act, on a motorway and an expressway the driver of a truck with a permissible gross weight over 3.5 t must not overtake another motor vehicle unless it can be done without obstructing traffic. With only a slight speed difference the overtaking would take a very long time, blocking the left-hand lane and holding up other vehicles.