Trailers and coupling systems
Types of trailer and coupling devices (fifth wheel, pin coupling, ball coupling), compressed-air and electrical connections, and safe coupling and uncoupling. Also the terms nose load, fifth-wheel load and towable trailer load, and the rules on towing trailers.
- 15 questions in this topic
- Topic 12 of 16 in the course: Bus & Coach – supplementary theory cat. D and D1
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From the key facts
- Coupling devices = trailer couplings on towing vehicles, towing devices on trailers and fifth wheels; secured against unintentional opening; marked with nose load and D-value or towable trailer load (VTS Art. 91).
- Check before driving off: reliably coupled, brakes and lighting working, no contact between the vehicles on bends (VRV Art. 70 para. 1).
All key facts, the questions with explanations and the exam simulation are part of the course.
Sample questions from this topic
3 of 15 questions free to try. All questions with explanations and the exam simulation are part of the course.
Question 1: What does the VTS count as coupling devices?
- Trailer couplings, towing devices and fifth wheels
- The compressed-air and electrical lines between the vehicles
- Only tow ropes, tow bars and towing dollies
Show answer
Correct answer: Trailer couplings, towing devices and fifth wheels
The VTS defines coupling devices as trailer couplings on towing vehicles, towing devices on trailers and fifth wheels. Lines and towing equipment do not come under this term.
Legal reference: VTS Art. 91 para. 1
Question 2: Which details must a non-standardised coupling device bear permanently and legibly, even when fitted?
- Approval mark, nose load and D-value or towable trailer load
- Number plate and keeper of the towing vehicle
- Date of the last lubrication and name of the workshop
Show answer
Correct answer: Approval mark, nose load and D-value or towable trailer load
Required are an approval mark with a number or the manufacturer or brand, the maximum permissible nose load and the D-value or the maximum permissible towable trailer load. Standardised devices marked accordingly are exempt from the load and D-value details.
Legal reference: VTS Art. 91 para. 4; VTS Art. 91 para. 5
Question 3: According to the vehicle registration document, the nose load could be higher than the value on the fitted trailer coupling. What applies?
- The lower value on the coupling device
- The higher value in the vehicle registration document
- The average of the two values
Show answer
Correct answer: The lower value on the coupling device
The permissible nose load is set by the vehicle manufacturer, but the nose load set by the manufacturer of the coupling device must not be exceeded. So the lower of the two values applies.
Legal reference: VTS Art. 91 para. 6
Legal references for this topic
The questions in this topic are based on these provisions:
- VTS Art. 8, 20, 91, 184, 189
- VRV Art. 5, 32, 68, 70, 72
- VZV Annex 11