Section 1

Legal regulations on interconnectivity and documents

Fixed combination means that a specific car is registered to tow a specific trailer. This may be because the coupling device is of a special type or due to other special circumstances. The trailer's registration number must then be stated on the car's registration certificate and the car's registration number on the trailer's registration certificate. You could say that the two vehicles can only drive with each other and not with anyone else.

Variable combination means that the car is registered to tow several specific trailers, which must also be stated in the car's registration certificate. A coupling certificate is also issued, which shows which trailers the car can be coupled with. The coupling certificate or a copy of it must be carried with you while driving. Beforehand, the car and the vehicles in question must be inspected together at an inspection company.

Sight-free coupling is the most common type of combination and means that the car and trailer can be coupled together without prior overall inspection by an inspection company. However, the car and trailer must be individually registered for blind coupling. On the basis of the registration certificates and by practical testing before driving, the driver must be able to determine whether the car and trailer match in terms of weight (including that the actual total weight of the trailer does not exceed the maximum weight of the trailer stated on the car) and in terms of width and length. In order to be approved for vision-free coupling, cars with a maximum permissible weight up to 3500 kg must be equipped with a 50 mm coupling ball. Similarly, trailers up to 3500 kg GVW must be equipped with a coupling part (ball cup).

The coupling device can also consist of a special coupling ("trailer hitch" or "NATO coupling").

Documents.
When driving, the car's and trailer's registration certificates and, if applicable, the coupling certificate must always be carried either in copy or in original.
When driving abroad, the original certificates or a copy (issued by SKAT) must be carried.

Fixed combination

Fixed combination is a very rarely used form of registration. Usually only used on older vehicles with e.g. 6 volt electrical system or in cases where the trailer is equipped with a special braking system (electric or hydraulic transmission), or perhaps a special coupling device.

The registration certificates shown are of the old type, but are still found among older vehicles and coupling devices.

Fixed combination

Registration certificates for fixed combination. Fixed combination means that the car is registered to tow a specific trailer The trailer's registration number must then be stated on the car's registration certificate. Here you can see the new registration certificates.

Axle pressure: The pressure transmitted to the road from the wheels on an axle.

B+ license: Provides a driving license for a combination of vehicles with a maximum total permissible weight of 4250 kg. where the trailer exceeds 750 kg. and the total permissible weight of the car must not exceed 3500 kg.

B+E license: Driving license valid for a car with a maximum permitted total weight of 3500 kg coupled to a trailer with a maximum permitted total weight of 3500 kg, totaling a maximum of 7000 kg. B+ and B+E are often referred to as "Trailer license".

Dual axle: Two axles on a vehicle that are positioned so close together that they effectively perform the same function as one axle. The advantages of a double axle on a trailer are better weight distribution and more stable steering and braking. Most trailers in the B+E context are double axle.

Service brake: Braking system on a vehicle that works "in service" i.e. while driving, as opposed to a parking brake that brakes the vehicle during "parking" i.e. when it is stationary.

Curb weight: The weight of a vehicle with the accessories that the vehicle normally carries (such as a spare tire). For the car, the weight of operating materials, fuel, lubricating oil, coolant and driver are not included. For cars with a registration certificate of "New" type, the weight is stated as the kerb weight. This means the car's factory weight plus the weight of oil, water, fuel and the driver (125 kg in total).

Trailer: A vehicle that is designed to be towed by another vehicle. Trailers are subdivided into trailers, semi-trailers and trailering equipment.

Trailer: A trailer other than a trailer or semi-trailer that has a special function, e.g. caravan or light shed trailer or similar.

Trailer: Is principally designed for the carriage of persons or goods, excluding semi-trailers.

Overrun brake: Service brake with a device that automatically applies the brake when the towing vehicle slows down.

Labeling: Sign or writing indicating specific weight limits.

Permissible load: The difference between permissible total weight and unladen weight.

Gross Vehicle Weight Rating (GVWR): The maximum permissible weight of the vehicle with operating equipment, driver and load at the time of registration or approval. (For trailers, only the load is usually included).

Implement coupling: Type of coupling that is only used for driving with a "non-registrable" trailer, such as a shed trailer or similar. Depending on the wheel cover, the driving speed must not exceed 15/30 km/h. and an anti-detachment device must be used.

Actual total weight: The current weight of the vehicle with operating equipment, driver and cargo.

Coupling certificate: Supplementary registration certificate. Certificate indicating which specific trailers a certain car is allowed to tow. (Variable combination).

Coupling ball: Ball mounted on the towing vehicle on which the coupling part of the trailer rests and is locked. Manufacturing dimensions: 50 mm. plus or minus 0.5 mm.

Combination: Is another term for pairing or two vehicles that are coupled together.

Ball coupling: The coupling part of the trailer that is bolted to the drawbar of the trailer.

Ball pressure: The pressure exerted by the trailer on the coupling ball. The trailer should be loaded in such a way that the ball pressure is approximately 5-10% of its actual total weight.

Safety chain or safety wire: Same term for the chain or wire used between vehicle and trailer. The chain/wire must be used when the trailer's permissible total weight is over 750 kg. and if this is over 1500 kg. it must be connected to the trailer's braking system in such a way that the trailer automatically brakes in the event of a break in the coupling device. (Also called "burst wire").
On single-axle trailers with a gross vehicle weight rating not exceeding 1500 kg, you can instead have a chain/wire that, in the event of vehicle separation, prevents the trailer drawbar from touching the ground and that can maintain some steering (the trailer remains "hanging" to the car).

Semi-trailer: Is principally designed for the carriage of persons or goods and is coupled to the towing vehicle in such a way that the vehicle and its load partly rest on the towing vehicle.

Road train: Car with an attached trailer.

"Single-axle" is the most common among small trailers, i.e. under 750 kg gross vehicle weight rating.

"Semitrailer" is not normally used in B+E combinations, but is often seen pulled by a tractor, or in larger versions as part of a "semitrailer train" over 3500 kg. permitted total weight.

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