Hauptuntersuchungen

Hauptuntersuchungen, commonly abbreviated as HU, are periodic safety inspections required for motor vehicles in Germany. They are mandated by the Straßenverkehrs-Zulassungs-Ordnung (StVZO) and aligned with European Union rules. The inspections are carried out by approved testing organizations, such as TÜV, DEKRA, GTÜ, or KÜS, at authorized inspection centers.

The HU assesses roadworthiness and compliance with safety and environmental standards. It covers critical vehicle systems including brakes, steering, suspension, tires, lights and signaling, seat belts, and body integrity, as well as emissions. The emissions test (Abgasuntersuchung, AU) is typically performed in connection with the HU for most passenger cars.

For passenger cars and most light vehicles, the first HU is due three years after the date of first registration; following inspections occur every two years. New vehicles are exempt from an HU during the first three years. Different intervals apply to other vehicle categories according to the law.

When the inspection is passed, the vehicle receives a certificate and a Prüfsiegel sticker for the license plate indicating the next due date. If defects are found, the vehicle may be declared unfit and require repairs followed by a reinspection; a failed inspection does not permit continued operation on public roads until the issues are corrected. An expired HU generally renders a vehicle illegal to drive on public roads until it passes the inspection.