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Denmark Category B/E car-and-trailer foundations study materials
Denmark Category B/E car-and-trailer foundations study resources

Denmark Category B/E car-and-trailer foundations practice questions

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Question 1Incident Environment

What should you do if your car breaks down on a motorway?

  1. Move to the emergency lane or verge if possible, warn others, leave the vehicle safely, and call for help Correct answer.
  2. Stay seated without warning lights until traffic clears
  3. Reverse along the hard shoulder to the last exit
  4. Try to repair the car in the live lane

Explanation

A motorway breakdown requires getting out of live traffic if possible, warning other drivers, moving occupants to safety, and contacting assistance.

Question 2Danish Framework

Under Danish driving regulations implemented following the EU Third Driving Licence Directive, what is the maximum permitted total weight (tilladt totalvægt) of a trailer that may be towed with a Category B/E driving license issued after January 19, 2013?

  1. 3,500 kg Correct answer.
  2. 4,250 kg
  3. 750 kg
  4. 5,000 kg

Explanation

Under current EU and Danish regulations (effective January 19, 2013), a Category B/E driving license permits towing a trailer or semi-trailer with a maximum permitted total weight (tilladt totalvægt) of up to 3,500 kg. When coupled with a Category B towing vehicle of up to 3,500 kg, the maximum combined total authorized mass of the vehicle train reaches 7,000 kg.

Question 3Danish Framework

A driver holds a standard Category B driving license. The passenger car has a permitted total weight of 2,100 kg, and the coupled trailer has a permitted total weight of 750 kg. The trailer is fully loaded to its 750 kg limit. Does the driver require a Category B/E license?

  1. Yes, because the combined total weight of 2,850 kg requires a commercial trailer endorsement
  2. Yes, because any trailer carrying heavy construction goods requires at least Category B+
  3. No, because Category B always permits towing a trailer with a permitted total weight up to 750 kg, provided the car does not exceed 3,500 kg Correct answer.
  4. No, but only if the driver has held the Category B license for at least three consecutive years

Explanation

Under Danish and EU driver licensing law, a Category B license holder is always entitled to tow a light trailer with a permitted total weight of up to 750 kg, regardless of the car's permitted total weight (up to 3,500 kg). The combination permitted mass can reach 4,250 kg (3,500 kg car + 750 kg trailer) on a standard Category B license.

Question 4Danish Framework

A van has a permitted total weight of 3,500 kg and is coupled to a flatbed trailer with a permitted total weight of 3,500 kg. Which driving license category is required to operate this 7,000 kg combination in Denmark?

  1. Category B/E Correct answer.
  2. Category B with Code 96 (B+)
  3. Category C1 without trailer endorsement
  4. Category D/E

Explanation

A Category B/E driving license entitles the holder to drive a Category B vehicle (up to 3,500 kg) coupled with a trailer of up to 3,500 kg permitted total weight. Together, this combination reaches the maximum possible 7,000 kg combination mass permitted under Category B/E.

Question 5Trailer Combination

How is the term 'faktisk totalvægt' (actual total weight) of a trailer defined under Danish traffic legislation?

  1. The trailer's empty weight plus the maximum theoretical design weight specified by the manufacturer
  2. The maximum gross weight registered on the trailer's official registration certificate
  3. The load limit stamped into the sidewalls of the trailer's road tires
  4. The current combined weight of the trailer including its entire cargo, passengers, and mounted equipment on the road Correct answer.

Explanation

Under Danish traffic regulations (Færdselsloven), 'faktisk totalvægt' is the real-time weight of the vehicle at any given moment, including the trailer's unladen structure, any installed accessories, and all cargo currently loaded. It is the physical weight that would be registered on a certified weighbridge.

Question 6Trailer Combination

A driver with a Category B/E license couples a trailer with a permitted total weight (tilladt totalvægt) of 2,500 kg to a passenger car whose registration certificate specifies a maximum towing capacity with brakes of 1,500 kg. What is the maximum actual total weight (faktisk totalvægt) the trailer may weigh on the road?

  1. Up to 2,500 kg, because Category B/E covers trailers up to 3,500 kg
  2. Up to 2,000 kg, calculated as the mathematical average of the two registration figures
  3. Up to 3,500 kg, provided the combined vehicle train does not exceed 7,000 kg
  4. Up to 1,500 kg, because the trailer's actual weight must never exceed the car's maximum towing capacity Correct answer.

Explanation

Although the driver holds Category B/E and the trailer is registered for 2,500 kg, the car's mechanical tow rating is legally binding on the road. The actual weight of the trailer (faktisk totalvægt) must never exceed the towing car's registered 'største tilladte påhængsvognsvægt med bremser' of 1,500 kg.

Question 7Trailer Combination

What critical vehicle handling danger arises when cargo is placed towards the rear of a trailer, producing negative nose weight (negativt kugletryk) on the towing ball?

  1. The car's rear axle is lifted upward, drastically reducing rear tire grip and inducing violent trailer snaking at modest driving speeds Correct answer.
  2. The car's front steering tires lose contact with the road while the rear brakes lock up completely
  3. The trailer's overrun brake damper becomes permanently locked in the compressed state
  4. The trailer's electrical wiring experiences an immediate short-circuit to ground

Explanation

Negative nose weight exerts an upward vertical lifting force on the car's tow hitch. This unloads the car's rear suspension, reducing rear tire lateral grip and making the vehicle combination exceptionally unstable, often triggering severe, uncontrollable snaking (slingren) even at speeds well below the speed limit.

Question 8Trailer Combination

If the car's towbar type approval plate specifies a maximum kugletryk of 75 kg, but the trailer's coupling head is stamped with a maximum kugletryk of 100 kg, what is the maximum legal nose weight for this combination?

  1. 100 kg, because the trailer manufacturer's specification always overrides the towing car
  2. 75 kg, because the lowest rated limit of the coupled components must never be exceeded Correct answer.
  3. 87.5 kg, calculated as the mathematical midpoint between the two ratings
  4. 175 kg, because the two component weight capacities combine additively

Explanation

When different components in a vehicle combination carry different maximum ratings, the lowest rated specification is always the binding legal ceiling. In this case, 75 kg is the lower limit and must not be exceeded to prevent overloading the car's towbar and rear axle.

Question 9Trailer Combination

How does nose weight (kugletryk) legally and physically affect the towing car's permitted payload (nyttelast) and rear axle load (akseltryk)?

  1. Nose weight does not count toward the car's mass because it is supported entirely by the trailer chassis
  2. Nose weight is added to the car's front axle capacity while deducting from the trailer load
  3. Nose weight is completely disregarded as long as the trailer tires have correct cold inflation pressure
  4. Nose weight transfers downward load directly onto the car's tow hitch, counting against the car's payload and rear axle load limit Correct answer.

Explanation

Nose weight is a vertical downward force acting directly on the towing car's hitch ball behind the rear axle. This vertical load counts directly as cargo weight on the towing vehicle, reducing the car's remaining payload capacity and increasing the load on the car's rear axle.

Question 10Trailer Combination

When inspecting a trailer's Danish registration certificate (registreringsattest) during a Færdselsstyrelsen test, what does the term 'Nyttelast' specify?

  1. The unladen empty weight of the trailer without accessories
  2. The maximum permissible vertical force exerted on the coupling ball
  3. The maximum legal weight of cargo, equipment, and goods that may be carried on the trailer Correct answer.
  4. The combined gross train weight of the towing vehicle and trailer

Explanation

On a Danish registration certificate, 'Nyttelast' (payload) specifies the maximum legal weight of cargo that the trailer may carry. It is calculated by subtracting the trailer's unladen weight (egenvægt / køreklar vægt) from its maximum permitted total weight (tilladt totalvægt).

Question 11Trailer Combination

A contractor needs to transport a compact mini-excavator. The car's registration certificate states: Tilladt totalvægt: 2,500 kg, Største påhængsvognsvægt m/bremser: 2,000 kg. The plant trailer's registration certificate states: Egenvægt: 600 kg, Tilladt totalvægt: 2,700 kg. Assuming the driver holds Category B/E, what is the maximum weight the excavator may have for this journey?

  1. 1,400 kg (so the trailer's actual weight of 2,000 kg exactly matches the car's maximum towing capacity) Correct answer.
  2. 2,100 kg (matching the trailer's registered payload capacity of 2,700 kg minus 600 kg)
  3. 2,700 kg (the trailer's registered permitted total weight)
  4. 900 kg (calculated by subtracting the trailer unladen weight from 1,500 kg)

Explanation

The car is only permitted to tow an actual loaded trailer weight (faktisk totalvægt) of 2,000 kg. The empty trailer weighs 600 kg. Therefore, the maximum allowable cargo (excavator) weight is 2,000 kg - 600 kg = 1,400 kg. Even though the trailer is technically rated for 2,100 kg of payload on its own papers, the towing car's 2,000 kg limit restricts the total physical weight.

Question 12Trailer Combination

During roadside weight enforcement by Danish Police and Færdselsstyrelsen, portable wheel scales record: car front axle: 1,050 kg; car rear axle: 1,350 kg (car permitted total weight: 2,300 kg); trailer axle: 1,400 kg; measured towball nose weight: 90 kg (car registered max kugletryk: 75 kg). Which legal violation has occurred?

  1. The trailer axle exceeds the 750 kg unbraked limit
  2. The car's front axle is overloaded by 50 kg
  3. No violation occurred because total combination weight is well below 7,000 kg
  4. Both the car's permitted total weight (2,400 kg vs 2,300 kg) and the maximum permitted nose weight (90 kg vs 75 kg) are exceeded Correct answer.

Explanation

The car's actual total weight is the sum of its front and rear axle loads: 1,050 kg + 1,350 kg = 2,400 kg. This exceeds the car's permitted total weight of 2,300 kg by 100 kg. Furthermore, the actual nose weight of 90 kg exceeds the car's 75 kg registered maximum kugletryk by 15 kg. Both represent serious statutory overload violations.

Question 13Trailer Combination

What is the standardized diameter of the spherical towball used for passenger car and light commercial vehicle trailers across Denmark and Europe?

  1. 50 mm Correct answer.
  2. 40 mm
  3. 65 mm
  4. 75 mm

Explanation

The standardized spherical coupling ball (kuglekobling) for passenger cars and light commercial vehicles up to 3,500 kg in Denmark and throughout the EU is 50 mm in diameter, manufactured according to ISO 1103 and UNECE Regulation 55.

Question 14Trailer Combination

What is the primary safety function of the breakaway cable (sprængwire / sikkerhedswire) on a trailer equipped with an overrun brake (påløbsbremse)?

  1. To prevent the trailer from swaying in crosswinds while driving
  2. To activate the trailer's emergency handbrake mechanism to bring the trailer to a stop if it detaches from the car while driving Correct answer.
  3. To provide an electrical earth grounding connection between the car chassis and trailer body
  4. To lock the trailer's jockey wheel into the upright travel position

Explanation

The breakaway cable (sprængwire) connects the trailer handbrake lever to the towing vehicle. If the trailer becomes uncoupled while driving, the cable is pulled taut, pulling the trailer's emergency handbrake fully on to stop the runaway trailer before the cable snaps or its shear ring releases.

Question 15Trailer Combination

How must the breakaway cable (sprængwire) of a braked trailer be attached to the towing vehicle according to Danish road safety regulations?

  1. Looped loosely over the neck of the towball so it can easily slide off during uncoupling
  2. Tied securely with a knot around the vehicle's exhaust pipe
  3. Attached to a dedicated eyelet, approved loop, or specialized bracket on the towbar structure Correct answer.
  4. Wrapped tightly around the trailer's jockey wheel shaft

Explanation

Danish and European regulations mandate that the breakaway cable must be attached to a dedicated eyelet (fastgørelsesøje) or approved bracket on the car's towbar structure. Simply looping it over the towball is dangerous because if a detachable towball unlatches or fractures, the cable would slip off without engaging the trailer's emergency brake.

Question 16Trailer Combination

Which lighting function is supported by a modern 13-pin ISO 11446 electrical trailer socket that is NOT available on a standard 7-pin ISO 1724 socket?

  1. Reversing lights (baklys) Correct answer.
  2. Left and right turn signals
  3. Tail position running lights
  4. Brake stop lights

Explanation

The older 7-pin connector (ISO 1724) only provides turn signals, tail lights, brake lights, and a rear fog light. The modern 13-pin connector (ISO 11446) adds dedicated pins for reversing lights (baklys), permanent +12V unswitched battery power, ignition-switched power, and separate ground returns.

Question 17Trailer Combination

What is the primary mechanical function of the hydraulic damper (støddæmper) fitted inside the trailer's overrun brake assembly (påløbsbremse)?

  1. To keep the trailer bed level when driving over uneven railway crossings
  2. To dampen sliding drawbar movement, preventing harsh, jerky trailer braking when the car decelerates Correct answer.
  3. To pump hydraulic fluid to high-pressure disc brake calipers on the trailer wheels
  4. To recharge the caravan's auxiliary 12V leisure battery during braking

Explanation

The overrun brake damper provides controlled hydraulic resistance as the drawbar compresses during car deceleration. It prevents the trailer from slamming forward violently into the car hitch, smoothing out the braking force transfer to the trailer wheel brakes and cushioning the transition when accelerating again.

Question 18Trailer Combination

What is the function of the auto-reverse mechanism (bakautomatik) installed in the wheel drum brakes of modern braked trailers?

  1. It automatically turns on the towing vehicle's hazard flashers whenever reverse gear is engaged
  2. It electronically steers the trailer wheels in the opposite direction when backing up
  3. It automatically releases the car's electronic parking brake when reverse torque is detected
  4. It allows the trailer to be reversed without the overrun brake locking the wheels, by releasing brake shoe pressure as wheels turn backward Correct answer.

Explanation

When reversing, the car pushes the trailer rearward, which naturally compresses the overrun hitch drawbar. The auto-reverse mechanism (bakautomatik) uses a pivoting shoe or cam inside the drum brake that detects backward wheel rotation and disengages the leading brake shoe, preventing the trailer brakes from locking up while backing.

Question 19Trailer Combination

Why must grease, oil, or protective paint NEVER be present on the towball when coupling a trailer equipped with a friction stabilizer hitch (slingrekobling, e.g., AL-KO AKS)?

  1. Grease and paint contaminate the internal friction pads, destroying their friction coefficient and ability to suppress sway oscillations Correct answer.
  2. Grease causes the hardened steel of the towball to corrode rapidly through galvanic reaction
  3. Grease acts as an electrical insulator that permanently disables the trailer's taillights
  4. Grease causes the breakaway cable to slip off the tow hitch assembly during emergency maneuvers

Explanation

Friction stabilizer couplings rely on high-friction composite pads pressed tightly against the towball to dampen pitch and yaw oscillations. Any grease, oil, or paint film coats the pads, rendering them completely ineffective at dampening snaking and requiring costly pad replacement.

Question 20Trailer Combination

What is the correct and safe chronological sequence when uncoupling a heavy trailer from a towing car on level ground?

  1. Release the coupling handle, drive the car forward 1 meter, then apply the trailer handbrake and lower the jockey wheel
  2. Apply the trailer handbrake, use chocks if needed, lower and secure the jockey wheel, disconnect the electrics and breakaway cable, release the coupling, then extend the jockey wheel until the coupling is clear Correct answer.
  3. Unclip the breakaway cable, unplug the electrics, lift the coupling release handle, and push the trailer backwards by hand
  4. Wind down the jockey wheel until the rear tires of the towing car are completely lifted off the ground, then release the hitch

Explanation

The safety sequence first prevents trailer movement with the handbrake and, where needed, chocks. Support the drawbar with the lowered and secured jockey wheel, disconnect the electrical connection and breakaway cable, release the coupling head, and extend the jockey wheel until the head lifts clear of the towball.

Question 21Trailer Combination

If a trailer's breakaway safety cable (sprængwire) is found to have broken wire strands, severe kinks, or a distorted attachment ring during a pre-trip inspection, what is the required action?

  1. Wrap the damaged section tightly with industrial electrical tape or heavy cable ties
  2. Tie a double knot in the cable to bypass the frayed section
  3. Replace the damaged breakaway cable with an approved new safety cable before driving Correct answer.
  4. Continue driving if the planned journey is less than 50 kilometers

Explanation

A damaged or kinked breakaway cable may fail under tension, snapping before it can exert sufficient pulling force to engage the trailer's emergency handbrake in a detachment event. Under Danish road safety rules, damaged emergency safety equipment must be replaced immediately prior to operating on public roads.

Question 22Trailer Combination

After coupling a trailer to the car, what must be done with the jockey wheel (næsehjul) before driving away?

  1. Wind the wheel fully up, ensure the wheel fork is seated into its anti-rotation travel slots, and tighten the clamp handle firmly Correct answer.
  2. Lower the wheel so that it contacts the road surface to carry approximately 15% of the tongue weight during driving
  3. Remove the jockey wheel completely and store it inside the passenger compartment
  4. Leave the clamp handle loose so the wheel can caster freely around tight corners

Explanation

Before driving, the jockey wheel spindle must be wound fully up into its travel position with the wheel fork locked into the frame cutouts (to prevent vibration from unscrewing it), and the outer clamp handle must be tightened securely. If a jockey wheel drops while driving, it can strike the road surface, catapulting the trailer or destroying the coupling.

Question 23Trailer Combination

Why is it unsafe to merely loop a braked trailer's breakaway cable over the neck of a detachable towball without clipping it to an approved chassis/towbar bracket?

  1. Because the trailer's electrical brake control module will trigger false dashboard error codes
  2. Because if the detachable towball mechanism unlocks or shears, the cable slips off with the ball, failing to activate the trailer's emergency brake Correct answer.
  3. Because the friction between the steel cable and towball neck will overheat the trailer hitch
  4. Because the cable will become tangled in the trailer's spare tire carrier

Explanation

If a detachable towball becomes unlatched or its neck fractures under fatigue, both the trailer coupling and the ball detach together. If the breakaway cable is merely looped around the ball neck, it will slide away with the ball without pulling the handbrake lever, allowing the disconnected trailer to roll freely across traffic.

Question 24Trailer Combination

During a vehicle check, the candidate notices that the rubber accordion bellows (gummimanchet) on the trailer's overrun drawbar is torn open. What hazard does this defect cause?

  1. The trailer's 13-pin socket will suffer an internal short circuit due to moisture migration
  2. The trailer's suspension springs will instantly lose damping capability
  3. The towball will immediately become undersized even though it is outside the bellows
  4. Road dirt, grit, and moisture will contaminate the sliding shaft, leading to corrosion, binding, or total seizure of the overrun brake Correct answer.

Explanation

The rubber bellows protects the precision-machined slide tube and greased guide bushings from water, road salt, and abrasive sand. If torn, contaminants enter the housing, causing rapid corrosion and slide shaft seizure, which either locks the trailer brakes permanently or prevents them from activating.

Question 25Trailer Combination

When driving away from a stop and applying the car brakes gently, what symptom indicates that the trailer's overrun brake damper (støddæmper) is completely worn out or broken?

  1. A loud metallic clunk or violent shudder as the trailer slams unchecked against the car towbar when decelerating Correct answer.
  2. The car pulls strongly to the left while braking in a straight line
  3. The trailer wheels instantly lock up and skid whenever reverse gear is selected
  4. The trailer's hazard lights flash automatically at speeds below 30 km/h

Explanation

When an overrun damper has lost its hydraulic fluid or internal seals, it cannot resist the forward surge of the trailer. When the car brakes, the trailer pushes in rapidly without resistance, producing a harsh metallic bang as the mechanism bottoms out, followed by a jerk when pulling away.

Question 26Trailer Combination

Which trailer tyre-and-wheel check matches the Category B/E practical-test curriculum and requires no workshop tools?

  1. Drive at 80 km/h and listen through an open window
  2. Kick each tyre and accept it if the sound is similar
  3. Check that tyres have at least 1.6 mm tread, no visible damage or abnormal shape, and that rims and bearings show no damage or significant play Correct answer.
  4. Jack up the trailer during the roadside test and dismantle the hub

Explanation

The official B/E curriculum calls for a visual and hands-on roadworthiness check: tyres must have at least 1.6 mm tread and no damage or abnormal shape; rims must be undamaged; and wheel bearings must have no significant play. The practical test does not require the candidate to jack up or dismantle the trailer.

Question 27Trailer Combination

How is 'trailer snaking' (slingren / fishtailing) defined in the context of driving dynamics?

  1. Uncontrolled, alternating lateral yaw oscillations of the trailer around its vertical axis that destabilize the towing car and can lead to a jackknife or rollover Correct answer.
  2. The normal bouncing movement of trailer leaf springs when driving across speed bumps
  3. The slight inward tracking of trailer tires when navigating a roundabout
  4. The gradual loss of air pressure from a trailer tire valve over several weeks

Explanation

Trailer snaking (slingren) refers to unstable lateral yaw oscillations where the trailer swings rapidly from side to side. Because the trailer is coupled behind the car's rear axle, these lateral forces push the car's rear end back and forth, quickly overpowering tire grip and leading to vehicle rollover if not promptly corrected.

Question 28Trailer Combination

Why is the common myth of 'accelerating out of a snake' considered exceptionally dangerous by driving safety authorities like Færdselsstyrelsen?

  1. Because accelerating causes the trailer's safety cable to snap immediately
  2. Because accelerating automatically disables the car's anti-lock braking system (ABS)
  3. Because accelerating adds kinetic energy and drives the vehicle further above its critical stability speed, amplifying oscillations into a catastrophic crash Correct answer.
  4. Because accelerating causes the trailer hitch to uncouple from the towball

Explanation

Snaking occurs when operating at or above the combination's critical speed. Accelerating increases speed and kinetic energy, which drastically magnifies the lateral yaw forces. Once the sway amplitude exceeds the grip of the car's rear tires, the car spins out or rolls over.

Question 29Trailer Combination

What is meant by the 'critical speed' (kritisk hastighed) of a vehicle combination consisting of a car and trailer?

  1. The specific threshold speed above which lateral yaw oscillations of the trailer become self-amplifying rather than damping out naturally Correct answer.
  2. The maximum speed limit posted on red circular road signs along Danish motorways
  3. The maximum design speed certified by the trailer tire manufacturer
  4. The minimum speed required to engage the trailer's overrun brake mechanism

Explanation

Critical speed is the physical velocity threshold where a combination's natural damping becomes zero. Below critical speed, any lateral sway caused by a wind gust or bump naturally dies out. Above critical speed, any disturbance triggers self-amplifying yaw oscillations that quickly escalate into violent snaking.

Question 30Trailer Combination

How do sudden strong crosswinds on exposed bridges (such as the Storebælt or Lillebælt bridges) affect a high-sided trailer or caravan combination?

  1. Crosswinds push the car forward, decreasing fuel consumption by approximately 15%
  2. Crosswinds exert substantial lateral pressure on the trailer's large side surface, inducing a yaw moment that can instantly initiate severe snaking Correct answer.
  3. Crosswinds increase the vertical downward kugletryk on the car towball, improving rear wheel traction
  4. Crosswinds have no measurable physical effect on combinations fitted with tandem axles

Explanation

High-sided trailers, horseboxes, and caravans present a large surface area to side winds. Sudden gusts-especially when passing bridge pylons or exiting bridge wind shields-generate massive lateral forces and yaw moments that push the trailer sideways, which can immediately trigger snaking if the combination is traveling too fast.

Question 31Trailer Combination

How does an electronic Trailer Stability Program (Trailer-ESP / TSA) in a modern towing vehicle detect and stabilize a snaking trailer combination?

  1. It deploys emergency aerodynamic spoiler fins from the trailer roof
  2. It increases engine torque to power through the oscillation and straighten the combination
  3. It sounds an audible buzzer inside the cabin and flashes hazard warning lights without applying brakes
  4. It detects yaw rate oscillations via chassis gyro sensors, cuts engine throttle, and applies selective pulsed braking to individual car wheels to counteract the sway Correct answer.

Explanation

Trailer Stability Assist (TSA / Trailer-ESP) uses the car's yaw and lateral acceleration sensors to detect the characteristic sinusoidal yaw frequencies caused by a snaking trailer. The system automatically intervenes by cutting engine torque and applying precise, individual wheel braking (often alternating left and right front wheels) while decelerating the combination below critical speed.

Question 32Trailer Combination

How does low tire inflation pressure on the towing car's rear axle or on the trailer tires affect the dynamic stability of a vehicle combination?

  1. It reduces the tires' cornering stiffness and lateral guidance force, substantially lowering the combination's critical snaking speed Correct answer.
  2. It increases stability by creating a wider rubber contact footprint on the pavement
  3. It eliminates the danger of jackknifing when reversing around sharp corners
  4. It automatically offsets the dangerous effects of negative nose weight at highway speeds

Explanation

Underinflated tires have soft sidewalls that flex excessively under lateral loads, dramatically reducing the cornering stiffness (sideføringskraft) of both the car's rear axle and trailer axle. This allows lateral oscillations to build up much more easily, significantly dropping the critical speed and making snaking far more likely.

Question 33Trailer Combination

What is the primary operational mechanism of a mechanical friction stabilizer coupling (slingrekobling, such as AL-KO AKS or Winterhoff)?

  1. It rigidly welds the trailer drawbar to the car frame to eliminate articulation
  2. It clamps integrated friction pads tightly against the dry 50 mm towball under heavy spring pressure, creating mechanical friction that dampens pitch and yaw movements Correct answer.
  3. It activates the trailer's electric brakes through extra pins in the 13-pin socket
  4. It allows the trailer to swivel 360 degrees freely without ever contacting the car bumper

Explanation

A friction stabilizer coupling (slingrekobling) features internal friction pads made of brake-lining material. When the stabilization lever is pressed down, heavy springs clamp the pads against the sides of the dry 50 mm towball, creating rotational friction that dampens minor yaw and pitch oscillations before they can escalate into full snaking.

Question 34Trailer Combination

What happens to a vehicle combination's yaw inertia (massetræghedsmoment) when heavy cargo is loaded at the extreme front and extreme rear of a trailer (the 'dumbbell effect'), even if the measured nose weight remains within legal limits?

  1. The yaw inertia decreases significantly, making the combination feel lighter in highway curves
  2. The critical snaking speed increases by at least 20 km/h
  3. The trailer's overrun brake automatically applies 50% more braking force to the wheels
  4. The yaw moment of inertia increases drastically, making sway oscillations far more violent and difficult to damp out once initiated Correct answer.

Explanation

Concentrating masses far away from the trailer's center of gravity and axle (like a dumbbell) dramatically increases the trailer's polar moment of inertia around its vertical yaw axis. Even though static nose weight might measure correctly, once the trailer begins to rotate or sway, the huge rotational momentum resists damping and creates extreme instability.

Question 35Trailer Combination

When descending a long, steep hill with a heavy car and trailer combination, what is the correct technique to control speed and maintain stability?

  1. Select a lower gear early to utilize engine braking, maintain a moderate controlled speed, and apply the footbrake firmly in brief, straight-line intervals if speed increases Correct answer.
  2. Shift the transmission into neutral and rely exclusively on gentle, continuous dragging of the footbrake pedal
  3. Accelerate down the slope so that the car maintains continuous pulling tension on the trailer hitch
  4. Partially engage the trailer handbrake using the lever to generate continuous drag throughout the entire descent

Explanation

Descending in a lower gear harnesses engine braking to restrain vehicle speed without overheating the friction brakes. If speed creeps up, the driver applies the footbrake firmly for brief periods to bring speed down, and then releases the pedal, allowing the brakes to cool and keeping the combination stable.

Question 36Trailer Combination

In heavy rain on a motorway, what specific hazard threatens a car towing a heavy trailer when encountering standing water in road wheel ruts?

  1. The trailer tires will instantly weld to the road due to rapid evaporative cooling
  2. The towing car's tires may hydroplane (aquaplane); loss of the car's steering or lateral rear grip allows the heavy pushing trailer to cause an uncontrollable jackknife Correct answer.
  3. The trailer's overrun damper will compress permanently, causing tire deflation
  4. The trailer's breakaway safety cable will corrode and snap within seconds from road spray

Explanation

If the towing car hits standing water and hydroplanes (aquaplanes), its tires lose contact with the road surface, eliminating all steering and lateral guidance forces. The heavy momentum of the trailer behind will push the floating car sideways, initiating a violent and unrecoverable jackknife.

Question 37Trailer Combination

When exiting a wind-sheltered highway forest cutting onto an elevated open bridge or viaduct in strong gusty conditions, what preventive driving action should a trailer driver take?

  1. Accelerate by 15 km/h to increase wheel gyroscopic stability
  2. Move immediately into the leftmost overtaking lane to clear roadside turbulence
  3. Reduce speed well before reaching the open section, hold the steering wheel firmly with both hands, and prepare for immediate lateral wind deflection Correct answer.
  4. Deactivate the car's electronic stability control (ESP) to ensure unassisted manual steering

Explanation

The transition from a sheltered tree-lined cutting to an open bridge creates an abrupt aerodynamic step-change. High-sided trailers receive a sudden lateral wind impact that can violently initiate snaking. Preemptively slowing down elevates the stability margin and ensures the vehicle is traveling well below critical speed when the gust hits.

Question 38Trailer Combination

Under European standard EN 12195-2 for synthetic webbing lashing straps, what does the designation 'LC' stamped on the identification label indicate?

  1. Length of Cord (the total length of the strap webbing in meters)
  2. Lashing Condition (the permissible ambient operating temperature range)
  3. Lashing Capacity (the maximum allowable direct tensile force the strap can safely bear in straight pull) Correct answer.
  4. Longitudinal Compression (the maximum crushing force the strap can apply to cargo)

Explanation

On a certified lashing strap label, 'LC' stands for Lashing Capacity (Surringskapacitet), expressed in decanewtons (daN). It defines the maximum allowable pulling force that the strap can safely sustain in direct tension during operation.

Question 39Trailer Combination

How should heavy, dense cargo (such as cement bags, gravel, or paving stones) be distributed on an open utility trailer?

  1. Stacked completely against the front headboard to maximize nose weight to the absolute limit of the coupling
  2. Loaded at the very rear against the tailgate to make unloading faster and easier
  3. Hung outside the trailer sideboards using specialized cargo brackets
  4. Placed low on the trailer floor, centered directly over or slightly ahead of the trailer axle(s), and secured firmly against movement Correct answer.

Explanation

Dense, heavy cargo should be placed as low as possible to maintain a low center of gravity. Positioning it centered directly over or slightly ahead of the axle(s) ensures that the trailer axle supports the mass while maintaining the correct positive nose weight (kugletryk) on the towball without overloading the car's rear suspension.

Question 40Trailer Combination

What is meant by 'form-fit' cargo securing (formslutning / blokering) on a trailer?

  1. Wrapping the cargo tightly with plastic stretch film around the trailer rails
  2. Stowing cargo flush against the trailer's front headboard, sideboards, or rigid blocking wedges so that it has zero gap to move Correct answer.
  3. Tying ropes in a complex figure-eight pattern around the trailer springs
  4. Stacking cargo in a circular pyramid shape to minimize frontal wind resistance

Explanation

Form-fit securing (formslutning) is a positive locking method where cargo is loaded directly against sturdy vehicle boundaries, such as the front bulkhead (headboard), side walls, stanchions, or tailored timber blocking. Because there is no gap for the cargo to accelerate into, the structural walls absorb the dynamic forces directly.

Question 41Trailer Combination

A driver needs to transport a large cylindrical item (such as a steel pipe or cable drum) on a flatbed trailer. What combined restraint method is necessary to secure it safely?

  1. Heavy-duty wedges or chocks secured firmly to the trailer deck on both sides of the cylinder, combined with direct or top-over lashings and edge protectors Correct answer.
  2. Relying exclusively on the heavy weight of the cylinder to maintain contact with the trailer floor
  3. Tying a single thin nylon cord over the top of the cylinder to the side rails
  4. Leaving the cylinder free to roll against the rear tailgate so it does not strike the front headboard during stops

Explanation

Cylindrical objects have minimal contact area with the floor and will roll under minimal lateral or longitudinal force. They must be immobilized using purpose-built chocks or wedges securely fastened to the floor, combined with high-capacity lashings over the top or through the core with corner protectors.

Question 42Trailer Combination

When reversing a car and trailer in a straight line, which direction should the driver turn the top of the car's steering wheel to steer the rear of the trailer to the RIGHT?

  1. To the right
  2. Keep the steering wheel centered without making any corrections
  3. To the left Correct answer.
  4. Turn the steering wheel fully from lock to lock three times

Explanation

When reversing, turning the steering wheel to the left swings the rear of the car to the right. This pushes the trailer's hitch coupling to the right, which pivots the trailer around its axle and steers the rear of the trailer to the right. To move the trailer's rear right, turn the wheel left.

Question 43Trailer Combination

What is 'corner cutting' (spordifferens / hjørneafskæring) when turning a car and trailer around a sharp right corner at a street intersection?

  1. The trailer wheels track wide outside the car's turning arc, swinging into oncoming traffic
  2. The car's front drive wheels slide sideways across the road surface
  3. The trailer's overrun brake automatically engages to slow the vehicle down
  4. The trailer wheels follow a tighter radius than the car, tracking inside the car's path and threatening to mount the curb or strike cyclists Correct answer.

Explanation

Because a trailer is towed from a point behind the car's rear axle and has fixed rear wheels, its wheels take a shortcut across the inside of any curve (spordifferens). When turning right, the trailer tracks closer to the inside curb than the car, requiring the driver to make a wider arc to clear curbs, poles, and bicycle paths.

Question 44Trailer Combination

What is the 'pivot point' (drejningspunkt) around which a single-axle trailer rotates during turning and reversing manoeuvres?

  1. The center of the towing car's front steering axle
  2. The center of the trailer's tire contact patch on the ground Correct answer.
  3. The towball coupling point on the rear of the car
  4. The center of the trailer's front bulkhead

Explanation

A single-axle trailer rotates around the contact patch where its tires meet the road surface. This contact line forms the fulcrum (drejningspunkt) around which the trailer body pivots when the towball pushes or pulls the front drawbar.

Question 45Trailer Combination

What is 'jackknifing' (saksning / knækning) during a reversing manoeuvre with a car and trailer?

  1. The trailer wheels locking up due to low brake fluid pressure
  2. The trailer bouncing vertically off the towball on rough ground
  3. The articulation angle between car and trailer becoming so acute that the car can no longer straighten the trailer, causing the drawbar to collide with the car body Correct answer.
  4. The car's front drive tires spinning on wet grass while attempting to move forward

Explanation

Jackknifing (saksning) occurs when the angle between the towing vehicle and the trailer becomes too sharp during reversing. Once past the critical angle, continuing to reverse will only force the trailer tighter into the car body, damaging bumpers, taillights, and trailer drawbars without straightening the trailer.

Question 46Trailer Combination

What is the correct immediate corrective action if a driver notices the trailer beginning to jackknife excessively while reversing?

  1. Continue reversing while turning the car steering wheel faster in the same direction
  2. Apply the car handbrake firmly and rev the engine in reverse
  3. Sound the horn to warn pedestrians and continue reversing slowly
  4. Stop immediately, shift into forward gear, pull forward several meters to straighten the vehicle combination, and restart the reverse manoeuvre Correct answer.

Explanation

Once a trailer passes the critical jackknife angle, no amount of steering in reverse can recover the alignment; continuing to reverse will only force the trailer harder into the car bumper. The only correct and safe action is to stop immediately, drive forward in a straight line to straighten out the combination, and then re-attempt the reverse manoeuvre with smaller steering corrections.

Question 47Trailer Combination

When are supplementary towing side mirrors (sidespejle / campingvognsspejle) legally required on a towing vehicle in Denmark?

  1. Whenever the trailer or its cargo is wider than the towing car, or obstructs the required field of view through standard interior and exterior mirrors Correct answer.
  2. Only when towing a multi-axle commercial plant trailer on motorways
  3. Exclusively during nighttime driving or in foggy weather conditions
  4. Only if the trailer has a registered permitted total weight exceeding 2,500 kg

Explanation

Under Danish Detailforskrifter for Køretøjer, supplementary extended towing mirrors are mandatory whenever the trailer body or cargo is wider than the car body, or prevents the driver from obtaining the legally required rearward view along both sides of the trailer. Standard car mirrors are obstructed by wide box trailers and caravans.

Question 48Trailer Combination

How does the length of the trailer drawbar (the distance from the coupling ball to the trailer axle) affect the trailer's steering behavior when reversing?

  1. A short drawbar reacts very slowly and requires large steering movements to turn
  2. Drawbar length has no measurable effect on trailer turning dynamics or reaction speed
  3. A long drawbar causes the trailer to jackknife almost instantaneously with the slightest steering wheel movement
  4. A short drawbar reacts very quickly and articulates sharply to steering inputs, whereas a long drawbar reacts more slowly and predictably Correct answer.

Explanation

Trailers with short drawbars (such as small utility trailers) articulate rapidly and can jackknife with very small steering inputs, demanding rapid and precise counter-steering. In contrast, long-drawbar trailers (like boat trailers or caravans) react more gradually and predictably, giving the driver more time to correct the line.

Question 49Trailer Combination

On a tandem-axle trailer (bogietrailer) with two closely spaced non-steering axles, where is the effective theoretical pivot point located during tight low-speed turns?

  1. Directly centered on the leading front axle
  2. Midway between the two axles, which causes noticeable tire scrub (dækskuring) as the tires are forced sideways Correct answer.
  3. Directly centered on the trailing rear axle
  4. At the hitch ball coupling point on the car

Explanation

Because both axles on a tandem trailer are fixed and non-steering, the trailer pivots around the geometric midpoint between the two axles. In tight turns, the tires on both axles are forced to slide laterally across the road surface, creating tire scrub (dækskuring) and noticeable turning resistance.

Question 50Trailer Combination

What is the recommended steering technique for maintaining a straight reversing line with a trailer down a long, narrow driveway?

  1. Turn the steering wheel continuously in wide zig-zags from lock to lock
  2. Hold the steering wheel firmly against the left lock and reverse at high speed
  3. Disengage the clutch, step out of the car, and guide the combination by pushing it in neutral
  4. Make small, prompt steering corrections as soon as the trailer begins to drift in either mirror, immediately counter-steering to follow the trailer Correct answer.

Explanation

Reversing in a straight line requires proactive micro-corrections. As soon as a sliver more of the trailer appears in the right mirror (indicating it is drifting right), the driver turns the wheel slightly to the right to push the trailer back, and immediately straightens and counter-steers to follow it before excessive articulation develops.