The doors of the vehicle should not be opened before it is completely stopped. This is important to **ensure the safety** of both the vehicle's occupants and other road users.

- **Preventive driving**: When opening a vehicle's door, it is crucial to ensure that you are not in the blind spot of other vehicles. Opening the door while the vehicle is still moving could cause accidents, as you do not have full control over the environment.

- **Emergency situations**: Even in emergency situations, such as when a vehicle cannot continue driving, you must wait until the vehicle is completely stopped before opening the doors. People should exit the vehicle only when it is safe to do so and always with the vehicle stationary.

- **Traffic regulations**: In situations where the vehicle must stop, such as at level crossings or movable bridges, it is essential that the vehicle is completely immobilized before passengers can exit. This ensures there is no risk of getting trapped or causing an accident.

Therefore, opening the doors before the vehicle is completely stopped is **prohibited** to avoid dangerous situations and ensure road safety.