What is the maximum permissible length of dimension X?

You answered correctly. In Germany, the maximum permissible width for loads on roads is generally 2.55 meters, but for certain agricultural vehicles and loads like hay, the absolute maximum allowed can be up to 3 meters, as long as safety is not compromised. Dimension X in the image refers to the total width of the load, so the correct answer is 3 meters. Knowing this helps you ensure loads are legal and safe when transporting wide agricultural goods.