Certain technical modificationsmust be inspected immediately by the technical inspection authority or an officially recognized inspection organization (DEKRA, GTÜ, KÜS, TÜV):

• Change of vehicle type

• Change in cubic capacity or power

• Increase in the maximum speed determined by the design

• Reduction of the maximum speed determined by the design if this is relevant to the driving license or if tires of lower speed classes are to be used

• Modification of the permissible axle loads, the gross weight, the payload, fifth-wheel load, trailer load or towing capacity

• Increase in vehicle dimensions, except for passenger cars and motorcycles

• Changes to the number of seats, berths or standing room in buses and coaches

• Changes to the exhaust or noise values, provided they have an impact on vehicle tax or traffic bans

These technical modifications must be entered in the vehicle documents by the competent authority.