There are a lot of rules, requirements and safety regulations you need to know and follow when driving with a trailer coupled to a car.
Firstly, you need to figure out if your driver's licence entitles you to tow the trailer. Then you have to find out which weight limitations apply to the car and trailer, the appropriate tow ball weight, brake requirements, how the load is to be secured and how fast you may drive.
Before driving with a trailer coupled to a car, you need to know the following:
Always ensure that the vehicle combination is permitted before coupling a trailer to a car.
B class driver's licence
Extended B class driver's licence
Example 1: The car's total weight is 2,300 kg and the trailer's total weight is 1,000 kg. Since the combined total weight does not exceed 3,500 kg, a B class driver's licence is sufficient.
Example 2: The car's total weight is 2,450 kg and the trailer's total weight is 1,550 kg. Since the combined total weight exceeds 3,500 kg, but is less than 4,250 kg, an extended B class driver's licence is required.
Example 3: The car's total weight is 2,870 kg and the trailer's total weight is 1,450 kg. Since the combined total weight exceeds both 3,500 kg and 4,250 kg, neither a B nor an extended B class driver's licence is sufficient.
If the car and trailer's combined total weight exceeds 3,500 kg a B class driver's licence is not sufficient for the vehicle combination
Car's kerb weight: The weight of the car with the driver when it is unloaded and fully equipped (with tools, spare wheel, fuel, engine oil and water).
Trailer's kerb weight: The weight of the trailer when it is unloaded.
Gross weight: The actual weight of the car or the trailer at a certain moment. This means the gross weight varies depending on load and equipment.
Maximum load: The car or trailer's maximum permitted load according to the registration certificates.
Total weight: Kerb weight + maximum load.
Keep in mind that both the car and trailer can have limitations regarding total weight and maximum load. Even if you have the correct driving licence, it does not automatically mean that your car can tow the trailer or that the trailer can handle the load. Details of this can be found in part 1 of each vehicle's registration certificate.
The picture below shows the part of a car's registration certificate containing this information.
If you have a B class driver's licence and are going to couple a trailer to a car, there are three things you need to check in the registration certificate.
1. That the trailer's total weight does not exceed the value stated in O.3 of the car's registration certificate.
2. That the trailer's gross weight does not exceed the value stated in O.1 of the car's registration certificate.
3. That the combined gross weight of the car and the trailer does not exceed the value stated in F.3 of the car's registration certificate (or 3,500 kg.)
If you drive with a coupled trailer that is too heavy, you risk driving off the road or causing an accident, as the car will behave differently than you are used to. For example, it can start to wobble or become under or oversteered, meaning it may turn more or less than usual. Braking distances may also be many times longer.
If you drive with a coupled trailer that is too heavy, you can also be found guilty of unlawful driving, which may result in a fine and a revoked driving licence.
Reversing with a coupled trailer is associated with certain risks because of poor rear visibility and more difficult manoeuvring. Keep in mind that you may only reverse if you can do so without endangering or obstructing other road users.
When reversing you always have to give way to all other road users. In case of an accident it is, generally speaking, the fault of the one reversing. This is the case even if you have asked someone to keep watch while you are reversing.
When reversing with a coupled trailer you must be patient, reverse slowly – using small steering movements – and wait for the trailer to catch up
Note that driving with a coupled trailer on slippery roads is associated with special risks. Read more about driving with a trailer in slippery conditions.
The tow ball weight is the weight a trailer coupling device exerts on a car's tow bar. The correct tow ball weight is usually between 50 and 100 kg.
Always check that the tow ball weight is correct before departure
It is the weight of the load and its position on the trailer that determines the tow ball weight: heavy loads at the back of the trailer push the coupling device upwards, which lowers the ball weight, while heavy loads at the front of the trailer press the coupling device downwards, therefore increasing the ball weight.
Insufficient tow ball weight
Excessive tow ball weight
When loading something on a trailer or on a car's roof, it is extremely important to position, anchor and brace the load correctly so that it cannot be displaced or fall off. If something does fall off onto the road, you must immediately remove it or, if it that is not possible, mark the object and then remove it as soon as you can.
The best way to load a trailer is to distribute the load as evenly as possible. A single heavy object is best positioned right above or just in front of the trailer's axle or axles.
Avoid placing a heavy object at the front and a heavy object at the back of the trailer, as this gives the trailer a tendency to wobble.
Use tensioning straps to hold the load in place and brace the load if necessary. Bracing the load means that you, for example, place planks of the correct length between the load and the front part of the trailer so that the load cannot move forward when you brake.
If any part of the load is liable to fall off, it must be covered and secured with a tarpaulin or the like. Neither cargo, straps nor tarpaulin may drag on the road or hang loose outside the car or trailer. The load or anchorage must also not create unnecessary noise or dust formation.
In the situation shown in the picture, the trailer load must be covered and secured before departure
The load securing (for example, tensioning straps and planks) must withstand 80% of the weight load forwards and half the weight load backwards and sideways. If you carry a snowmobile weighing 310 kg on the trailer this means that the load securing must withstand the pressure of 248 kg forwards (310 × 0.8 = 248) and 155 kg backwards and sideways (310 × 0.5 = 155).
Remember that the load must not diminish the car or trailer's lighting or obstruct the view of the licence plates. Neither must the load obstruct your visibility or the manoeuvring of the car. Also, be aware that protruding loads in some cases must be marked.
Vehicle length - The total vehicle length, including load, must not exceed 24 metres.
Vehicle width - The total vehicle width, including load, must not exceed 260 centimetres.
Vehicle height - The vehicle height is normally not something you need to consider when driving a car, but you still need to know that roads in Sweden normally have a clearance of at least 4.5 metres.
If the clearance in an underpass or similar is less than 4.5 metres, the road sign Limited vehicle height will be used.
Trailers with a total weight exceeding 750 kg must be equipped with a service brake. Trailers coupled to private cars are usually equipped with an overrun brake that brakes automatically when the car brakes.
Trailers with a kerb weight exceeding 400 kg must also be equipped with a parking brake.
You may never driver faster than 80 km/h with a coupled trailer or caravan
Front: Two white reflectors. If the trailer is wider than 160 cm, two lights are also required.
Sides: At least one orange light and one orange reflector on each side. If the trailer exceeds six metres, more lights and reflectors are required.
Rear: Two red rear lights and brake lights, two red triangle reflectors, a white light that illuminates the registration plate and indicators on each side.
After you have ensured that your car may tow the trailer, that you are allowed to drive the vehicle combination and that the load is secured, you must carry out a safety check.
The picture below shows the coupling device on a braked trailer and its most important parts.
1 - Overrun brake
2 - Electrical plug
3 - Security wire
4 - Parking brake
5 - Coupling device
If your car has an engine failure and must be towed there are certain rules you need to follow. Towing should be done on the road's hard shoulder, or, if there is no hard shoulder, on the far right of the carriageway. On motorways and clearways, towing must be done on the hard shoulder and only to the first suitable exit. When towing, 30 km/h is the highest permitted speed.
Hazard warning lights may be used on the towed car, but not on the towing vehicle.
The tow rope must be marked if it exceeds 2 metres. There are no rules for how it should be marked, other than that it should be marked clearly.
The tow rope must be marked if it exceeds 2 metres
If the towed car's lights are broken, the car must be marked during dark or foggy conditions.