You can install a ski box or roof rack on the roof of a car.
If you have installed a ski box, you must put the goods you want to transport in the ski box and not on top of that box.
If you have placed a load on the roof of the car, you must ensure that the load on the sides of the car does not protrude more than 20 centimeters on each side. A marking sign is not required if the load protrudes from the roof of a car.
The load may not protrude more than 1 meter at the front and rear of the car.
Also, the total width of the car + load may not exceed 2.55 meters. If you drive on an unpaved road, the car + load may not exceed 2.20 meters. Load may not be transported directly on the roof, but must be transported with a load carrier on the roof.