1. Drivers are obliged to warn other road users about the manoeuvres that they intend to carry out with their vehicles (article 44.1 of the articulated text).
Any change of intent, direction or lane must be indicated so that other road users are able to know how to manoeuvrE. The most common infractions in this sense are drivers who do not signal changing lane when overtaking, both when starting and when they rejoin the original lane, when they intend to exit a roundabout and when leaving a parking lot, the latter two being the most common infractions.
2. As a general rule, these warnings will be made using the vehicle’s indicators or, failing that, with the arm (article 44.2 of the articulated text).
The validity of those carried out with the arm will be subordinated to the fact that they are perceptible by the other road users and are carried out in accordance with the provisions of the following article, and will annul any other optical indication that contradicts them.
In case one of the signals breaks, it can be replaced by signals with the arm, which will be valid if they are done in line with regulations and as long as they are visible to other road users.
These hand signals can only be used as a temporary solution to a problem. As a general rule, you will not be able to drive the vehicle with the indicators not working, using hand signals, as the vehicle fault it is a sanctionable offence.