To safely and legally drive a commercial vehicle, van, or any vehicle towing a trailer, you must fully understand the strict rules regarding vehicle weights, size limits, and loading procedures.
1. Vehicle Weights Explained
Vehicle categories on driving licences strictly depend on the weight of the vehicle. The different terms you must know are:
- β’Unladen weight: The weight of the vehicle when it is not carrying any passengers, goods, or other items. It includes the body and all parts normally used with the vehicle or trailer. It does not include the weight of fuel or batteries in an electric vehicle (unless it's a mobility scooter or powered wheelchair).
- β’Mass in running order: The total weight of a vehicle when it is empty but ready to be used on the road. For cars, buses, and lorries, this includes the driver, the body, all normal parts, essential fluids (like oil), and a full tank of fuel. For motorbikes and mopeds, it does not include the driver (up to 75kg), batteries for electric vehicles, or fuel storage tanks.
- β’Maximum Authorised Mass (MAM) / Gross Vehicle Weight (GVW): The weight of a vehicle or trailer including the maximum load that can be carried safely when it is being used on the road. It is listed in the owner's manual and normally shown on a plate or sticker fitted to the vehicle.
- β’Gross Train Weight (GTW) / Gross Combination Weight (GCW): The total weight of the tractor unit plus the trailer plus the load.
- β’Down-plating: If a vehicle is unlikely to be used at its potential maximum weight, it may be 'down-plated', meaning a lower weight is legally shown on the vehicle's plate.

πΌοΈ Vehicle identification number (VIN) and weight limit plate
2. Licence Requirements for Vans and Towing
- β’With a standard car driving licence (Category B), you can drive a van up to 3,500kg MAM, or a zero-emission (electric or hydrogen-powered) van up to 4,250kg MAM.
- β’Licences issued before 1 January 1997: You can usually drive a vehicle and trailer with a combined weight of up to 8,250kg MAM. You are also allowed to drive a minibus with a trailer over 750kg MAM.
- β’Licences issued from 1 January 1997: You can tow a trailer that weighs up to 3,500kg MAM (known as a 'category BE' vehicle).
- β’To tow combinations heavier than this, you must apply for a provisional licence for a medium-sized lorry and trailer (category C1+E), pass the lorry theory test, and pass the C1+E driving test. This allows you to drive vehicles and trailers with a combined weight of up to 12,000kg MAM.
3. Towing Weight and Width Limits
If your VIN plate does not list a train weight, you should not use your vehicle for towing.
- β’Maximum width: The maximum trailer width for any towing vehicle is 2.55 metres.
- β’Maximum length (up to 3,500kg MAM): If your vehicle's MAM is 3,500kg or less, you cannot tow a trailer that is longer than 7 metres.
- β’Maximum length (over 3,500kg MAM): If your vehicle's MAM is more than 3,500kg, the maximum lengths are 12 metres for the trailer, 18 metres for the vehicle and trailer combined, and 3.05 metres for how far the load can overhang the back of the trailer. Maximum lengths do not include the A-frame (the frame that connects your car to the trailer).
- β’Unbraked Trailers: A loaded trailer with no braking system must not weigh over 750kg, and should not weigh more than 50% of your car's weight.
4. Vehicle Towing and Loading Rules (Rule 98)
When towing or loading a vehicle, as a driver:
- β’you MUST NOT tow more than your licence permits.
- β’you MUST NOT overload your vehicle or trailer. You should not tow a weight greater than that recommended by the manufacturer.
- β’you should distribute the weight in your caravan or trailer evenly with heavy items over the axle(s) and ensure a downward load on the tow ball. This minimizes the possibility of swerving or snaking.
- β’you MUST secure your load and it MUST NOT stick out dangerously. Any heavy or sharp objects and any animals must be secured safely.
- β’if your vehicle is narrower than your trailer or load, or your trailer/load obstructs your rearward view, then towing mirrors MUST be used.
- β’your trailer MUST be fitted with a secondary coupling device, such as a breakaway cable or a safety chain, which engages the trailer's brakes or stops it if it becomes detached.
- β’carrying a load or pulling a trailer may require you to adjust your headlights.
- β’you must not drive in the right-hand lane of a motorway with 3 or more lanes when towing.

πΌοΈ Car towing a caravan using approved towing mirrors and a breakaway cable