Overtaking and being overtaken in the theory test: rule 168 and slow-moving queues

When a driver is trying to overtake you, maintain a steady course and speed, slowing down if necessary to let them pass. That is rule 168 of the Highway Code, which also says never to obstruct drivers who wish to pass.

This page covers being overtaken, when you must not overtake, what to do in a slow-moving queue of traffic, and the space to leave for other road users. Every rule is from the Highway Code on gov.uk and the rule numbers are given so you can check them.

When you are being overtaken (rule 168)

Rule 168 gives four instructions:

• Maintain a steady course and speed. Slow down if necessary to let the vehicle pass.
• Never obstruct drivers who wish to pass.
• Do not speed up or drive unpredictably while someone is overtaking you. The rule calls this dangerous.
• Drop back to keep a two-second gap if someone overtakes and pulls into the gap in front of you.

Rule 169 adds that you should not hold up a long queue of traffic, especially in a large or slow-moving vehicle. Check your mirrors frequently and, if necessary, pull in where it is safe and let traffic pass.

You're driving in a slow-moving queue of traffic

Two rules apply here, and they point the same way: stay in your lane.

• Rule 151 (slow-moving traffic) says not to change lanes to the left to overtake. It also says to leave enough space to manoeuvre if the vehicle in front breaks down, and to allow access to and from side roads (rules 103 to 158).
• Rule 163 says to stay in your lane if traffic is moving slowly in queues. If the queue on your right is moving more slowly than you are, you may pass on the left.

Rule 151 also says to be aware of cyclists and motorcyclists who may be passing on either side, and to allow pedestrians and cyclists to cross in front of you.

When you must not overtake (rules 165 to 167)

Rule 165 lists situations where you must not overtake, including:

• if you would have to cross or straddle double white lines with a solid line nearest to you
• the nearest vehicle to a pedestrian crossing, especially when it has stopped to let pedestrians cross
• if you would have to enter a lane reserved for buses, trams or cycles during its hours of operation
• after a "No Overtaking" sign and until you pass a sign cancelling the restriction

Rule 166 says not to overtake if there is any doubt, or where you cannot see far enough ahead, such as at a corner or bend, a hump bridge or the brow of a hill.

Rule 167 says not to overtake where you might come into conflict with other road users. Examples include approaching or at a junction, where the road narrows, at a level crossing, and where traffic is queuing at junctions or road works. Our road markings guide explains the white lines.

Overtaking left and right (rule 163)

Rule 163 says to overtake on the left only if the vehicle in front is signalling to turn right and there is room to do so. Before overtaking, rule 162 says to make sure:

• the road is sufficiently clear ahead
• road users are not beginning to overtake you
• there is a suitable gap in front of the road user you plan to overtake

Rule 163 also says to use your mirrors, signal, take a sideways glance into the blind spot if necessary, and move back to the left as soon as you can without cutting in.

Space for vulnerable road users and large vehicles

Rule 163 gives these minimum clearances as a guide (source):

Road user	Clearance
Cyclists, at speeds up to 30 mph	At least 1.5 metres, and more at higher speeds
Horse riders and horse-drawn vehicles	Pass at under 10 mph, with at least 2 metres
Pedestrian walking in the road	At least 2 metres, at a low speed

If you cannot meet these clearances, rule 163 says to wait behind rather than overtake. Our vulnerable road users guide covers these road users. For large vehicles, rule 164 says overtaking is more difficult: drop back, make sure you have room to finish, and if in doubt do not overtake. See our HGV and LGV guide for more.

Practise before the test

The free practice questions let you try these rules in question form. If you are booking your test, the test centres page lists centres by city.

Check what you remember

Try the free theorytest.ai diagnostic to see whether overtaking is a weak area. theorytest.ai is independent and is not affiliated with the DVSA. Gov.uk does not publish test questions, so we cannot say how many are about overtaking.

Frequently asked questions

What does Highway Code rule 168 say?

Rule 168 covers being overtaken. Maintain a steady course and speed, slow down if necessary, and never obstruct drivers who wish to pass.

You're driving in a slow-moving queue of traffic. What should you do?

Stay in your lane and do not change lanes to the left to overtake (rules 151 and 163).

When can you overtake on the left?

Only if the vehicle in front is signalling to turn right and there is room. In slow queues you may pass on the left if the right-hand queue is moving more slowly (rule 163).

How much room should you give a cyclist when overtaking?

At least 1.5 metres at speeds up to 30 mph, and more at higher speeds (rule 163).

Can you overtake just before a pedestrian crossing?

No. You must not overtake the nearest vehicle to a pedestrian crossing, especially when it has stopped to let pedestrians cross (rule 165).