The total width of the car and the load must not exceed 260 centimetres. The load may project a maximum of 20 centimetres sideways on either side.
If you drive a car that is 180 centimetres wide, any load may project 20 centimetres to the right and 20 centimetres to the left.
If you drive a car that is 240 centimetres wide, any load may only project 20 centimetres to the right or 20 centimetres to the left. The load may also project 15 centimetres to the right and 5 centimetres to the left. Or 10 centimetres on either side.
A load that projects sideways does not need to be marked.