Quick answer
When towing a trailer or caravan, lower limits apply: 50 mph on single carriageways and 60 mph on dual carriageways and motorways. On a motorway with three or more lanes you must not use the far-right lane. Stay within your vehicle and trailer weight limits, and load evenly.
Hooking a trailer or caravan onto the back of your car changes how it behaves in almost every way. It is longer, much heavier, slower to speed up and slower to stop, and it can sway from side to side if you have loaded it badly. Because of that, the rules of the road tighten up the moment you attach a trailer, and the theory test expects you to know them.
The good news is that the rules are logical once you see the pattern. Speed limits drop, one motorway lane is off-limits, and your weight and licence limits all point in the same direction: give yourself more room, more time and a lower, more balanced load. Get those basics right and towing becomes calm and predictable rather than nerve-wracking.
This guide walks through the speed limits, the lane restriction, the licence and weight rules that changed in December 2021, and the practical loading tricks that keep a trailer tracking straight behind you. We finish with the emergency technique for a trailer that starts to snake, because knowing it in advance is what stops a wobble becoming a crash.
Study time
26 min
Level
Core
Confidence
+10%
Practice
15 Qs
What you'll be able to do
- Understand how to load a car or van so it stays safe to drive — and why where you put the weight matters.
- Understand who is legally responsible for a vehicle's load — and why it's always you.
- Understand the basics of towing safely — including what to do if a trailer starts to sway.
The facts that matter
- A car towing a trailer or caravan is limited to 50 mph on single carriageways, where the normal limit for cars is usually 60 mph.
- On dual carriageways and motorways the towing limit is 60 mph, even though an unladen car may go up to 70 mph there.
- On a motorway with three or more lanes, a vehicle towing a trailer must not use the far-right (outside) lane except in special circumstances such as a lane closure.
- Since 16 December 2021, most drivers who passed the car test can tow a trailer without taking a separate B+E test, but you must still respect your vehicle's and trailer's weight limits.
- Load a trailer with heavy items low down and over the axle, keep within the noseweight limit, and never exceed the maximum weight the trailer or towbar is rated for.
- Use proper towing mirrors so you can see behind the trailer, and check that its lights, indicators and number plate all work before setting off.
Make it stick
Memory anchors
Fifty–Sixty, Never Seventy
When towing, think '50 and 60, never 70'. It is 50 mph on single carriageways and 60 mph on dual carriageways and motorways. The 70 mph limit simply never applies to you while a trailer is attached, so the '7' is switched off.
Heavy, Low, Over the Axle
Picture the trailer's axle as a see-saw pivot. Put the heaviest items low down and directly over the axle so nothing tips the balance. Weight too far back makes it snake; too far forward overloads the towbar. Centre it and it tracks straight.
Stay sharp
The mistakes everyone makes
Thinking motorway means 70 mph
Many drivers assume the motorway limit is always 70 mph, but with a trailer attached it drops to 60 mph. Sitting at 70 while towing is both illegal and far less stable. Keep it at 60 and leave the outside lane alone.
Loading everything at the back
Piling luggage at the rear of a trailer, behind the axle, is a classic cause of snaking. The tail wags the car. Always load heavy items low and over or just ahead of the axle, and secure everything so nothing shifts on the move.
Braking hard when it starts to sway
A driver's instinct when a trailer snakes is to brake or steer sharply, but that usually makes the sway worse. The correct response is to ease off the accelerator gently, hold the wheel steady and let the outfit settle.
Out on the road
What this looks like in real life
A caravan holiday on the motorway
You are towing a caravan up the M6 to the Lake District and the traffic is light, so it feels natural to cruise at 70. But your legal limit is 60 mph, and the far-right of the three lanes is off-limits to you entirely. Settling into the middle or left lane at 60 keeps you legal and gives the caravan a stable, steady airflow behind it. It also means faster traffic can flow past you without confusion.
The snaking trailer at speed
A driver loads a box trailer with the heaviest tools stacked at the very back and heads onto a dual carriageway. At around 55 mph the trailer begins to sway from side to side, tugging the car with it. Remembering the drill, the driver lifts off the accelerator smoothly, keeps the steering straight and avoids the brakes. The outfit gradually settles. Afterwards they repack the load low and over the axle, and the sway does not return.
Quick answers
Frequently asked questions
What speed can I do when towing on a motorway?
The limit is 60 mph on motorways and dual carriageways when you are towing a trailer or caravan, not the 70 mph that applies to a solo car. You must also stay out of the far-right lane on a motorway with three or more lanes.
Do I need a special licence to tow a trailer?
Since 16 December 2021, most drivers who passed the standard car test can tow a trailer without a separate B+E test. You must still keep within the maximum weights your car, towbar and trailer are rated for, so always check the plates.
Why does my trailer sway or 'snake' at speed?
Snaking is usually caused by loading too much weight at the back, an overloaded trailer, or too little noseweight. If it happens, ease off the accelerator gently, hold the wheel steady and do not brake hard or steer sharply. Then repack the load low and over the axle.
Do I have to use towing mirrors?
If your normal mirrors do not give a clear view of the road behind the trailer or caravan, you must fit extension towing mirrors. They let you see following traffic and are a legal requirement when your standard mirrors are blocked by the load.
Turn towing rules into marks
Reading builds understanding — practice makes it stick. Pick up where this guide leaves off, free.
Revision checklist
0/6Tick each point once you can explain it without looking.