The Contraflow System: Everything You Need to Know

cycle contraflow in Liverpool

Interpreting all the different types of road markings and signposts can be tricky, especially when you come across ones that aren’t very common. Chances are that the first time you ever heard of the contraflow system was when you were studying for your theory test—and it sounds like a lot to learn, right? Thankfully, it’s actually pretty simple to get the hang of. So, even if your theory test is tomorrow, you can still make sure you get those all important marks.

We’ve got the lowdown on contraflow bus and cycle lanes, contraflow roads on the motorway, and how you should drive when you find yourself in the midst of a contraflow system. By the end, you’ll be the font of all knowledge—on this topic, at least. Here goes!


What is a contraflow system?

‘Contra’ means against, while traffic ‘flow’ refers to the movement of vehicles on any given road. So, a contraflow system is where traffic in one or more lanes on the same carriageway (side of the road) is directed the opposite way to normal—against the flow.

Contraflow systems can be either permanent or temporary. Most commonly, you’ll come across contraflow lanes being used on motorways, to keep traffic moving during periods of roadworks, or on one-way streets, where contraflow bus or cycle lanes allow ‘wrong way’ access to these vehicles.

Contraflow cycle lane

One way street with a contraflow cycle lane
Photo © Mike Quinn (cc-by-sa/2.0)

One-way streets are generally designed to keep traffic moving, but tend to disadvantage those on bikes. Cyclists may be tempted to ignore the signs and get round the restrictions by cycling the other way along the pavement—which puts pedestrians at risk. Alternatively, they may find themselves having to take roads riddled with dangers.

Separate contraflow cycle lanes offer a safer alternative, allowing cyclists to ride either direction along the road. This enables them to avoid busy routes and dangerous junctions, and, in turn, access their destinations quicker. Cyclists using contraflow lanes are less likely to be involved in accidents, and are less of a threat to pedestrians on pavements.

As a driver, you need to be aware of which direction any other person is travelling. Contraflow cycle lanes lessens the risks of those on pedal bikes, but they are still vulnerable road users, and can only keep safe when you know and observe the rules.

Make sure you’re familiar with the contraflow cycle lane signs, and always keep in mind road markings. Where there is a solid white line dividing a contraflow cycle lane from other vehicles, you must not cross it. Straying across dashed white lines is allowed, but only when necessary, and when you are sure it is safe to do so.

Contraflow cycle lanes are sometimes merged with contraflow bus lanes. In these cases, both bus drivers and cyclists will be travelling against the rest of the traffic.

Contraflow bus lanes

As with their cycle counterparts, contraflow bus lanes are usually found on one-way streets within cities, and help buses to shortcut busier roads.

According to Theory Test Pro, identifying the contraflow bus lane sign was the most commonly failed road sign question on their practice tests during 2017. That’s an easy mark to throw away—and when you’re only allowed 7 mistakes in total on the theory test, every bit of knowledge helps. Thankfully, this sign is one of the more non-cryptic ones. Study it, and you’ll soon be able to recognise where a contraflow bus lane is in force. Here it is, in all its glory.

Contraflow bus lane sign

As you can see, the contraflow bus sign consists of a blue rectangle with a bus on one side and a line down the middle. Arrows each side of the line indicate that buses will be travelling the opposite way to other traffic. So, whether or not you could draw the sign from scratch, you should be able to work out the meaning, so long as you’re clear on what contraflow means.

Contraflow system on motorways

Contraflow system on junction 9 of the m74
Photo © Bill Boaden (cc-by-sa/2.0)

Where the contraflow system may affect you the most, as a car driver, is when you’re travelling on a motorway or dual carriageway.

By definition, dual carriageways divide traffic travelling in different directions with a central reservation. Everyone on your side will be going the same way: with-flow traffic. It’s much safer to keep drivers separate on these roads, given the high speeds allowed.

When roadworks are taking place, you’ll often find just part of the carriageway closed. You might be told to merge into another lane, or warned of lower temporary speed limits in place. However, for more extensive works and repairs, you may find a contraflow system being enforced. The whole of one carriageway will be diverted across the central reservation and onto the opposite carriageway, to run concurrently with the traffic on that side.

Where this happens, you will usually be separated from oncoming vehicles only by traffic cones, and lanes are likely to be narrower than normal. To compensate for these increased risk factors, there will probably be a reduced speed limit in force, which you must observe.

When travelling through a contraflow system, try to get in the correct lane early, keep in that lane, and avoid any attempt at overtaking. You should follow other vehicles from a safe distance, and should not cross the line of cones, as you would end up travelling towards oncoming traffic.

Even if an emergency service vehicle is approaching from behind, it is recommended that you stick to your side of the road. After all, you don’t want to risk more injuries by putting yourself and others in harm’s way.

With-flow bus and cycle lanes

With flow bus and cycle lane sign

Just as you may be asked about the contraflow system during the theory test, you may also get questions on with-flow bus or cycle lanes. If contraflow means going against normal traffic, then with-flow means travelling in the same direction.

Be careful not to mix the two up, especially when identifying signs: the difference between contraflow and with-flow bus and cycle lane signs is that the latter don’t have arrows—everyone is travelling the same way.

The contraflow system on the theory test

There are a number of things you may be asked about contraflow systems on the theory test. Check that you know:

  • What you should do when you’re driving through a contraflow system
  • On which type of road you might find a contraflow bus or cycle lane
  • What different contraflow signs look like, as well as their with-flow equivalents
  • What happens to the speed limit where a contraflow system is in place on a motorway

If you’re not sure about any of these, you probably need to do a little more revision before sitting your theory—if so, check out our compilation of theory test revision resources. Read through our contraflow system guide again to grasp the key facts.


That’s it on the contraflow system—but do you know when you should enter a box junction, or if you’re ever allowed to undertake another vehicle?

By Katie Scott

Katie grew up in the middle of nowhere, so knows the true value of getting behind the wheel. From the rules of the road to handy hints and tips, she'll give you the lowdown on all things driving. Always on the move, when she's not in the car, you'll probably find Katie darting around the squash courts or out running in the rainy British countryside.

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