Quick answer
On a one-way street all traffic flows in a single direction. Choose your lane early: left lane to turn left, right lane to turn right. You may pass on either side, but never make a U-turn. Watch for contraflow bus or cycle lanes carrying traffic towards you.
One-way streets keep busy town and city traffic moving smoothly by sending every vehicle in the same single direction. They're common in shopping areas, around one-way systems and near junctions where two-way traffic would cause gridlock. Because everyone travels the same way, the usual habits of keeping left and overtaking only on the right no longer apply in quite the same way.
The key skill on a one-way street is reading the signs early and positioning your car for where you want to go. A blue circular sign with a white arrow tells you the direction of flow, while a red 'no entry' sign at the far end warns drivers not to enter against it. Get these two signs clear in your mind and half the challenge is solved.
This guide walks you through spotting the signs, choosing the correct lane, overtaking safely on either side, and the extra hazards you need to watch for — contraflow lanes, pedestrians looking the wrong way, and the strict ban on U-turns. Master these and one-way streets become one of the easier parts of town driving.
Study time
39 min
Level
Foundation
Confidence
+10%
Practice
49 Qs
What you'll be able to do
- Understand who has priority at junctions — and why right of way is something you're given, never something you take.
- Understand which lane to pick on a roundabout, and a simple clock trick that takes the guesswork out of every exit.
- Understand when it's safe to change lane or overtake — and the one junction you must never block.
The facts that matter
- All traffic on a one-way street flows in the same single direction — there is no oncoming traffic in the general lanes.
- The direction of flow is shown by a blue circular sign with a white arrow; a red 'no entry' sign marks the wrong end.
- Because traffic goes one way, you may overtake or pass other vehicles on either the left or the right.
- Get into the correct lane as early as you can: the left lane to turn left, the right lane to turn right.
- Never make a U-turn on a one-way street — you would end up facing oncoming traffic.
- Watch for contraflow bus or cycle lanes, where buses or cyclists may legally travel towards you against the flow.
Make it stick
Memory anchors
Blue means go, red means no
A blue circle with a white arrow shows the way the traffic flows — follow the arrow. A red 'no entry' sign means that end is closed to you. Blue = go this way, red = never this way.
Left to leave left
Line up early — sit in the left lane when you plan to turn left, and the right lane when you plan to turn right. Choosing your lane late means last-second swerving, which is exactly what one-way streets are designed to avoid.
Stay sharp
The mistakes everyone makes
Confusing the one-way arrow with a 'keep left' sign
A blue arrow pointing straight up means one-way traffic ahead. A 'keep left' or 'keep right' sign has its arrow set at an angle and tells you to pass an obstruction on that side. Read the angle: straight up is a direction of flow, angled is an instruction to pass. Mixing them up can send you the wrong way.
Only checking your right before changing lanes
On ordinary roads you overtake on the right, so drivers get into the habit of only watching that side. On a one-way street vehicles can legitimately pass on your left too. Check both mirrors and both blind spots before you move across.
Forgetting about contraflow lanes
Just because you're going one way doesn't mean everyone is. Contraflow bus or cycle lanes let buses or cyclists travel towards you against the main flow. Look for the road markings and signs, and never assume nothing can come the other way when crossing or turning.
Out on the road
What this looks like in real life
The town-centre shopping loop
You're driving through a pedestrianised shopping district on a one-way system. A blue arrow sign confirms the flow, so you relax about oncoming cars — but you spot a contraflow cycle lane marked on the right. A cyclist is heading towards you. You wait and check it's clear before turning across the lane, then continue. Reading that sign early stopped a nasty surprise.
Getting your lane right before a junction
Approaching the end of a one-way street, you need to turn left. Rather than staying central and cutting across at the last moment, you move into the left lane a good distance back while the traffic is light. When you reach the junction you simply flow left with no fuss. The driver beside you, who left it late, ends up stuck in the wrong lane.
Quick answers
Frequently asked questions
Can you overtake on the left on a one-way street?
Yes. Because all traffic on a one-way street travels in the same direction, you are allowed to pass other vehicles on either the left or the right. Always check your mirrors and blind spot on the side you're moving to first, as other drivers may pass you on either side too.
How do I know a road is one-way?
Look for a blue circular sign showing a white arrow in the direction of flow, usually posted at the entrance. At the opposite end you'll see a red 'no entry' sign facing anyone who might try to drive in against the flow. Road markings and lane arrows on the tarmac give further confirmation.
Are U-turns allowed on one-way streets?
No. Making a U-turn on a one-way street would leave you facing oncoming traffic, which is dangerous and against the rules. If you've gone the wrong way, continue to the end of the street and use a junction or side road to turn around safely.
What is a contraflow lane?
A contraflow lane is a marked lane where certain traffic — usually buses or cyclists — is legally allowed to travel against the general one-way flow, meaning towards you. They are shown by signs and road markings, so stay alert and never assume nothing can approach from the opposite direction.
Turn one-way streets 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.