At what monthly interval must trucks with a permissible total mass exceeding 3.5 t be presented for official inspection (Hauptuntersuchung)?

In Germany, trucks with a permissible total mass over 3.5 tons must undergo the Hauptuntersuchung (official inspection) every 12 months. This regular inspection ensures that the vehicle meets safety and environmental standards. The 12-month interval helps detect and fix potential defects early, maintaining road safety and vehicle reliability. It is important to remember that this applies specifically to heavier trucks, while other vehicle types may have different inspection intervals.