Why do loaded trucks have to pay a toll on the highways?

Countries, such as Austria, Switzerland, and Germany, through which many foreign trucks cross in order to transport goods across national borders are referred as 'transit countries'. Owing to the heavy load, the roads are often damaged and have to be repaired promptly. Therefore, since the beginning of 2005, trucks weighing more than 12 tons have to pay a tax for using the roads in the transit countries. The longer the distance travelled, the heavier is the tax levied.