Climbing lane: the sign and the rule
Updated •5 min read
A climbing lane, also called a crawler lane, is an extra lane provided on some hills. Use it if you are driving a slow-moving vehicle or if vehicles behind you want to overtake, and watch for the signs and road markings that show the lane is about to end (Highway Code rule 139).
That one rule is the whole of the Highway Code's advice on climbing lanes. This page sets out what it asks of you, the signs and markings you will see, and how the theory test asks about it. Our own page for rule 139 has the full wording.
What rule 139 says
Rule 139 sits in the Highway Code's section on general rules for all drivers and riders, straight after the rules for dual carriageways (137 and 138). It says three things:
- Climbing and crawler lanes are provided on some hills.
- Use the lane if you are driving a slow-moving vehicle, or if there are vehicles behind you wishing to overtake.
- Be aware of the signs and road markings which indicate the lane is about to end.
Rule 139 is advice, not a legal requirement: it does not use the word "must". The Highway Code's introduction says that breaking an advisory rule will not, in itself, lead to prosecution, but the Code may be used in evidence in court to establish liability (gov.uk: Highway Code introduction).
Who should use the climbing lane
| Situation | What rule 139 says |
|---|---|
| You are driving a slow-moving vehicle uphill | Use the climbing lane |
| Vehicles behind you want to overtake | Use the climbing lane |
| Neither applies | Rule 139 does not ask you to move over |
| The lane is about to end | Watch for the signs and markings that show it |
The lane lets faster traffic pass you safely instead of queuing behind you on the hill.
The signs and markings
Where the lane ends. Know your traffic signs shows rectangular information signs for the loss of a lane on a dual carriageway or one-way street. It says these signs "are often used at the end of a climbing lane and may include a distance" (gov.uk: Know your traffic signs, information signs). The same signs may be reversed to show the loss of the left-hand lane.
Lines on the hill. Know your traffic signs says double white lines are used "to separate opposing traffic flows on steep hills with climbing lanes" (gov.uk: Know your traffic signs, road markings). If the line nearer to you is solid, you must not cross or straddle it except in the cases rule 129 allows. If it is broken, you may cross to overtake when it is safe.
When the lane ends, the traffic in it has to rejoin the lane alongside. Plan this early, check your mirrors and signal, rather than racing to the end of the lane.
How the theory test asks about it
Road signs and markings, and rules of the road, are subject areas the car theory test must cover. The Highway Code is one of the three books gov.uk says the questions are based on (gov.uk: revision and practice). Gov.uk does not publish the questions, so we cannot say how often climbing lanes come up.
A typical question describes you driving slowly up a hill with traffic behind you, then asks what you should do. The answer comes straight from rule 139: move into the climbing lane so faster vehicles can pass. Try our practice question on a heavily loaded car meeting a crawler lane, which asks exactly this.
Wrong answers often say the lane is "only for lorries" or that you should speed up instead. Rule 139 says neither.
Related guides
- Road markings in the theory test: double white lines, hatched areas and other markings.
- Dual carriageways in the theory test: lane rules 137 and 138.
- Overtaking in the theory test: when overtaking is safe and legal.
Start free
Start free with the theorytest.ai diagnostic to see whether road rules and markings are a weak area for you. theorytest.ai is independent and is not affiliated with the DVSA or the Department for Transport.
Frequently asked questions
What is a climbing lane?
A climbing or crawler lane is an extra lane provided on some hills. Use it if you are driving a slow-moving vehicle or if vehicles behind you want to overtake (Highway Code rule 139).
Is a crawler lane the same as a climbing lane?
Yes. Rule 139 calls them "climbing and crawler lanes" and gives the same advice for both.
Do you have to use a climbing lane?
Rule 139 is advice, not a legal requirement. It says you should use the lane if you are slow or if vehicles behind you want to overtake.
What sign shows a climbing lane is ending?
Know your traffic signs shows rectangular signs for the loss of a lane, often used at the end of a climbing lane. They may include a distance.