It is necessary to put on the reflective vest when getting out of the vehicle on an interurban road to change a wheel. This is important for several reasons:

- Personal safety: The reflective vest increases the driver's visibility, especially in low-light conditions or on roads with fast-moving traffic. This helps prevent further accidents.

- Legal requirement: Regulations require drivers to carry a reflective vest in the vehicle and to wear it when leaving the car in emergency situations, such as a breakdown or an accident.

- Protection in emergencies: Before leaving the vehicle, it is essential to put on the vest to protect yourself and to properly signal the situation to other drivers.

For these reasons, you should always wear the reflective vest in these situations to ensure your safety and comply with the law.