When a vehicle stops on the shoulder of an interurban road due to a breakdown, it is **mandatory to put on the reflective vest before exiting the vehicle**. This is crucial to ensure the safety of the driver and passengers, as the vest makes them more visible to other drivers, especially in emergency situations.

- **Visibility and safety**: The reflective vest, which must be approved, is essential to increase the visibility of the driver and passengers when exiting the vehicle. This is especially important on interurban roads where vehicles travel at high speeds.

- **Procedure in case of breakdown**: If the vehicle cannot continue driving, it must be parked on the right shoulder or in a place where it causes the least possible obstruction. Before exiting the vehicle, all occupants must put on the reflective vest and seek a safe place.

- **Emergency signaling**: In addition to putting on the vest, it is necessary to turn on the emergency lights and, if possible, place the pre-warning light to alert other drivers of the presence of a stopped vehicle.

These measures are fundamental to protect the people involved and prevent additional accidents. Therefore, the reflective vest should always be used before exiting the vehicle on an interurban road.