1. The driver must warn by means of visible signals any manoeuvre that involves a lateral or rearward movement of their vehicle, as well as their intention to stop or slow down its progress considerably. Such optical warnings shall be made sufficiently in advance of the initiation of the manoeuvre, and, if they are lights, they shall remain in operation until the end of the manoeuvre.
Remember to signal overtaking correctly using indicators when starting and finishing overtaking.
Once the manoeuvre is done, do not forget to turn off the indicator, as it is considered a minor infraction to have an indicator on without intending to make a turn or change lanes.
2. For the purposes of the previous section, the following should also be taken into account:
A) The lateral movement will be indicated using the direction indicator light corresponding to the side to which it is going to be made, or the arm, in horizontal position with the palm of the hand extended downwards, if the displacement is going to be towards the side that the hand indicates, or bent up, also with the palm of the extended hand, if it is going to be towards the opposite direction.
In manoeuvres involving a sideways movement, it is this which is exclusively warned, so the warning must conclude as soon as the vehicle has adopted its new trajectory.
B) Reversing will be warned with the corresponding reversing light, if available, or, if not, extending the arm horizontally with the palm of the hand backwards.
C) The intention to stop the vehicle or to slow it down considerably, even when such events are imposed by the circumstances of the traffic, should be signalled, whenever possible, by the repeated use of the braking lights or by moving the arm alternately from top to bottom with short and fast movements.
When a vehicle is immobilised on a motorway, or in places or circumstances that significantly reduce visibility, the presence of the vehicle must be indicated by the use of the hazard lights, if available, and, where appropriate, with the position lights.
Remember that if you breakdown on the motorway and have to stop your vehicle on the hard shoulder, you must signal this by placing the emergency triangles on the road, one at the rear, or one at the rear and one at the front, according to the characteristics of the road.
If the immobilisation forces the vehicle to stop or park, the direction indicator light corresponding to the side to which it is to be carried out should also be used, if the vehicle has such a device.
3. For the same purpose, acoustic warnings may be replaced by the use of lights, even in town, using intermittently short or long-range lighting, or both alternatively, at very short intervals and so as to avoid glare.