Parking in **double row and leaving the vehicle without the driver** is considered a serious obstacle to traffic. This is because:

- **Parking in double row** means that the vehicle is blocking the passage of other vehicles that are properly parked or trying to circulate. This can cause congestion and hinder the flow of traffic.

- When the **driver leaves the vehicle**, there is no one who can move it quickly if necessary, which worsens the situation. This can prevent other vehicles from joining the road or performing necessary maneuvers for traffic.

- According to the regulations, parking in double row with the driver absent is classified as a **dangerous parking**, as it can create risk situations and obstruction on the public road.

For these reasons, leaving a vehicle in double row without the driver is an infraction that seriously obstructs traffic.