The annual technical inspection of cars is carried out to ensure the fulfilment of safety requirements, but also to control the emission of noise and harmful substances (NOx, CO etc.). This inspection has to be carried out by authorised garages, service centres or automobile clubs. Vehicles are checked for optimal tuning with regard to fuel consumption. If a vehicle does not fulfil certain criteria (e.g. emission targets, safety requirements), it will not be certified, i.e.it will not receive a label which must be fixed on the front windshield and is valid for one year (except for new cars, see below). A motor vehicle which is not labelled is no longer allowed to be used on public roads.For new cars and vans < 3,5 t gross vehicle weight, the first technical inspection has to be carried out after three years. The second inspection becomes due after further two years. After this period the car must be inspected every year. For cars without a valid adhesive label, a penalty has to be paid.