What is the maximum speed you are allowed to drive a truck with a permissible total mass of 4.0 t on autobahns?

For trucks with a permissible total mass of more than 3.5 tons but not exceeding 7.5 tons, the maximum speed allowed on autobahns in Germany is 80 km/h. This rule is set to ensure safety, as heavier vehicles need a longer distance to brake and can be more difficult to control at higher speeds. Because your truck weighs 4.0 tons, you fall under this regulation, so 80 km/h is the correct maximum speed. Knowing these speed limits helps you drive safely and legally on German highways.