THE OVERTAKEN VEHICLE: The driver’s obligations

Article 86. The driver’s obligations.
The driver who is indicated to that the vehicle behind intends to overtake must keep to the right hand side of the road, except whre turning or changing direction to the left or stopping on the same side referred to in Article 82,2, in which case he must keep to the left, but without interfering with the progress of oncoming vehicles (LST Art 35,1).
Where it is not possible to keep to the right hand side of the road and the overtaking can be done safely, drivers of vehicles referred to in paragraph 3 that are going to be overtaken will indicate it is possible to approaching traffic by extending the arm horizontally and moving it repeatedly backwards and forwards, with the back of the hand facing backwards, or by using their right hand indicator, when it is not advisable to use the hand signal.
The driver of the vehicle that is going to be overtaken is forbidden to increase speed or to carry out maneuvers that prevent or impede overtaking.
He is also required to reduce the speed of his vehicle when, once overtaking is started, some situation occurs that endangers his own vehicle, the overtaking vehicle, oncoming traffic or any other road user (LST Art 35,2).
Despite the previous paragraph, when the overtaking vehicle gives clear indication of abandoning the maneuver by reducing its speed, the driver of the vehicle which would have been overtaken is not required to reduce theirs, if by so doing it would endanger other traffic, although it is required to facilitate the return to his lane of the would-be overtaker.
Drivers of heavy vehicles, those of large dimensions or those required to observe a specific speed limit must reduce speed or use the hard shoulder, if practicable, to allow overtaking, when the oncoming traffic density, the insufficient width of the road, its profile or condition does not allow overtaking with ease and safety.
Infractions of this Article are considered serious offences (LST Art 65.4.c).