Sea 1 means no overtaking
Section 2 is no overtaking (all types of motor vehicles are prohibited, are allowed to pass two-wheeled motorcycles, mopeds).
Signal 3 is Forbidden overtaking by trucks (forbidden trucks with the largest weight over 3,5 tons overtaking other motor vehicles, only two-wheeled motorcycles, mopeds); other types of motor vehicles are allowed to overtake each other and trucks are allowed