Definition
A semi-trailer is a trailer built without a front axle, designed to be coupled to a tractor unit so that a substantial part of its weight rests on the tractor. Tractor + semi-trailer is the most common heavy-goods configuration on European roads.
Key facts
- No front axle: rests on the tractor via the fifth wheel.
- Maximum combined length: 16.50 m.
- Driving a tractor + semi-trailer requires a C+E licence (or D+E for passenger transport).
- Different from a full trailer, which has a front axle and only connects via the hitch.
Practice real questions on this topic
Free DGT 2026 test with exam-style questions and explanations. No signup. Or explore the free DGT test in English hub for everything in one place.
In the DGT exam
- A truck with a maximum authorised mass (MAM) of 2,500 kg and an age of 7 years is required to undergo a technical inspection...
- Under the general rule in Article 12.1, excluding the family or authorised-adult exception, how old must a passenger seated behind the rider of a two-wheeled moped be?
- To find a vehicle’s first registration date, which document should you consult?