The situation when the driver of a tractor decides to attach a trailer to the towed vehicle does not occur often, but raises a lot of questions among inspectors and road users. Theoretically, the presence of a trailer on a towed vehicle is not a direct ban on the use of a flexible hitch, but the practical implementation of such a maneuver turns into a complex engineering and legal task. The main problem lies not so much in the letters of the law, but in the physics of movement and controllability of such a composite structure.
The driver must be aware that when using flexible hitch (cable) the trajectories of the tractor and the towed vehicle will always differ, especially in turns. Adding a trailer to the rear of a towed vehicle creates a tail effect that becomes extremely unstable. Any sudden movement or gust of wind can cause the structure to collapse or skid, which poses a direct threat to road safety.
Before deciding on such towing, it is worth weighing all the risks. Drivers often forget that Traffic rules require that the towed vehicle be controlled by the driver behind the wheel. This means that a person with a license of the appropriate category must sit in the towed car, who will control not only the car itself, but also the behavior of the trailer behind it. Ignoring this rule can result in serious fines.
Legal aspects and traffic regulations requirements
Referring to the text Traffic rules, we will not find a direct ban on towing a car, which, in turn, drags a trailer. However, there are a number of conditions that make this process legal only if certain standards are strictly observed. Paragraph 20.4 of the traffic rules states that towing must be done using a flexible or rigid hitch or by partial loading. It is important that the width of the train does not exceed 2.55 meters, and the length of the rigid coupling is no more than 4 meters.
Particular attention should be paid to the category of rights of the driver driving the towed vehicle. If the trailer being pulled by the towed car weighs more than 750 kg, then the driver of this car will need a category license "BE" or higher, depending on the total mass of the composition. If the driver has only category “B”, and the weight of the trailer is large, then such actions will be regarded as driving a vehicle without the appropriate license, which entails a fine and evacuation.
⚠️ Attention: If the towed car does not have a driver with a license of the appropriate category, the traffic police inspector has every right to issue a fine for lack of documents and licenses, as well as to prohibit further movement.
It is also worth remembering the speed limit. When towing with a flexible hitch, the speed should not exceed 50 km/h. The presence of a trailer on a towed vehicle may require an even greater reduction in speed due to increased inertia and instability of the structure. Driving on highways with such a track may be prohibited or extremely dangerous due to the minimum speed limit.
Technical limitations of flexible coupling
A flexible hitch, or simply a tow rope, has its own physical strength limits. Standard cables, which can be purchased at any auto store, are designed for the weight of the towed vehicle. When the weight of the trailer and its cargo is added to the equation, the load on the cable increases by multiples. At the moment of a jerk when starting or braking, the force may exceed the breaking load of the cable, which will lead to its breakage and uncontrolled movement of the component part.
A critical parameter is the length of the cable. According to the rules, it should be from 4 to 6 meters. If the towed car has a trailer, this length becomes insufficient to dampen vibrations. A “pendulum” effect occurs when the inertia of the trailer begins to swing the towed vehicle from side to side. This phenomenon is technically difficult to control even by a professional driver.
The cable attachment also plays a role. Standard vehicle towing lugs are not always designed for dynamic loads with the additional weight of a trailer. With a sharp jerk, the eye can be torn out of the body, which will damage the side members or bumper. Usage rigid coupling in this case it would be more justified from a technical point of view, but it also has limitations in length and maneuverability.
Use only certified tow ropes with a safety margin of at least 30% of the calculated weight of the entire combination (vehicle + trailer + cargo).
The braking system of the towed vehicle must be in good working order when driving on a flexible hitch, since it is this system that dampens the inertia of the entire tail. If the trailer does not have its own brakes (which is often the case with light models), the entire load falls on the brakes of the towed vehicle, which can overheat and fail.
Controllability and physics of train movement
The physics of the movement of a road train, consisting of a tractor, a towed vehicle and a trailer, is radically different from the movement of a single vehicle. When turning, the rear axle of the towed vehicle cuts off its trajectory, moving towards the center of the turn. The trailer, in turn, tends to cut the trajectory even further. As a result, there is a risk that the trailer will “back up” a curb, hit a pedestrian, or crash into a guardrail, even if the tractor has made a clean turn.
When braking, the situation becomes even more critical. The inertia of the trailer will push the towed vehicle, which in turn will push the tow vehicle through the tensioned cable. Since the flexible coupling does not transmit braking force, but only traction force, stopping such a train becomes a difficult task. The cable will constantly sag and be pulled jerkily, making smooth braking almost impossible.
- 🚗 The trailer's skidding trajectory is always directed towards the inside of the turn, which requires a wide maneuver radius.
- ⛓️ A flexible clutch does not provide synchronized braking, creating an “accordion” effect.
- 🌬️ Side wind has a much stronger effect on a long train, increasing windage.
The tractor-trailer driver must be aware that he does not actually feel the full weight of the trailer through the clutch or cable until he begins to maneuver. All responsibility for controlling the “tail” falls on the driver of the towed car, who must constantly look around (which is prohibited by the rules when driving) or have perfect communication with the driver of the tow vehicle.
Required documents and permits
To legally carry out such towing, you must have a complete package of documents with you. In addition to standard licenses and insurance, permission to transport oversized cargo may be required if the width or length of the assembled road train exceeds established standards. Typically the width should not be more than 2.55m and the hitch length (auto + auto) is limited, but with a trailer the overall length can become an issue.
Insurance companies may refuse to pay in the event of an accident if it is proven that the towing was carried out in violation of the rules or without the appropriate insurance policy. In the policy OSAGO or CASCO There may be exceptions for cases of towing, especially if it is not carried out by a specialized tow truck. It is recommended to clarify the terms of the insurance contract in advance.
| Parameter | Traffic regulations | Recommendation with trailer |
|---|---|---|
| Speed | up to 50 km/h | up to 30-40 km/h |
| Hitch length | 4-6 meters | Maximum (6 m) |
| Driver in towed | Required | Mandatory (cat. BE) |
| Bus sign | Not required | Not required |
The absence of a driver in a towed vehicle when there is a trailer is a serious violation. In this case, no one will be able to steer to compensate for the trailer drifting, and no one will be able to brake if the cable breaks. Traffic police inspectors regard driving without a driver in a second car as creating an emergency situation.
Alternative transportation methods
Given the high risks and complications associated with towing a vehicle with a flexible trailer, it is wiser to consider alternative options. The safest and legally clearest way is to use a tow truck with a full load. In this case, the car is loaded onto the platform together with the trailer (if the carrying capacity allows) or the trailer is left and the car is taken away separately.
The partial loading method, where the front or rear wheels of the towed vehicle are on the tow truck bed, is also an excellent solution. In this case, the car is rigidly fixed, and the presence of a trailer does not matter, since it can also be partially submerged or uncoupled. This removes questions regarding the category of driver's rights of a towed car, since it is not being driven.
Is it possible to unhitch the trailer and leave it behind?
You can park your trailer on the side of the road or in a parking lot as long as it does not interfere with traffic or violate parking regulations. However, an unattended trailer may be stolen or towed by utility companies if it is found abandoned. It is better to find a guarded parking lot.
If using a tow truck is not possible, you can consider the option of a rigid hitch, but only if the design of the trailer and vehicle allows this without the risk of destruction of the components. A rigid coupling ensures a stable distance between the cars, which somewhat improves handling, but does not completely solve the problem of skidding in corners.
Safety checklist before driving
If you do make a firm decision to tow, you need to make thorough preparations. Ignoring even one point can cost you your car or your health. Check the technical condition of all components, make sure that all participants in the process are present and are ready for a complex maneuver.
☑️ Check before towing
Be sure to coordinate the signal system with the tractor driver. Since talking on the phone while driving is prohibited, and shouting through the glass is not always audible, use horns or lights. For example, one short beep means “attention”, two means “reduce speed”, continuous beep means “stop”.
⚠️ Attention: Reversing on a flexible trailer hitch is strictly prohibited! It is almost impossible to fold such a train back without damaging the cars.
Remember that in the dark or in poor visibility (fog, rain), towing with a trailer on a flexible hitch should be stopped. The visibility of the trailer's dimensions to other road users may be insufficient, which increases the risk of an accident. Turn on the hazard lights on both vehicles.
Frequently asked questions (FAQ)
Do I need to register a trailer if it is towed by a disabled vehicle?
Yes, the trailer must be registered with the traffic police, have a license plate and valid insurance (if required by weight), regardless of whether the vehicle pulling it is in good condition or not. Failure to register a trailer will result in a fine.
Can a tractor-trailer driver have a "B" category if the trailer is heavy?
The category of driver's rights of a tractor-trailer depends on the weight of his vehicle and the trailer he is towing (if any). But the key point is the driver of the towed car. If the trailer is heavy (>750 kg), the driver of the towed vehicle needs a "BE" license. A tractor driver only needs a “B” if his own train (car + trailer, if any) fits within the limits.
What happens if the cable breaks?
If the cable breaks, the towed vehicle and trailer will continue to move by inertia. Without a driver behind the wheel to brake or steer, this will result in an uncontrolled drift into the oncoming lane or sidewalk. This is the main reason why having a driver in a towed car is mandatory.
Is this kind of towing allowed on the highway?
Traffic regulations prohibit towing with a flexible hitch unless it allows you to maintain a speed of at least 40 km/h. It is extremely difficult and dangerous to accelerate with a trailer and consistently maintain such a speed on the highway, so formally this can be regarded as interfering with traffic.
Towing a car with a trailer on a flexible hitch is technically possible, but requires a driver with category "BE" in the towed car and carries a high risk of loss of control.