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Which Lane Should You Normally Drive In When Travelling On A Dual Carriageway?

Did you know a dual carriageway simply means a road with two single and completely separated lanes in either direction? That means there are some dual carriageways in the UK that only have one lane. For these, it is obvious which lane you should drive in, but what about dual carriageways with two or more lanes?

Drive on the left

You should always drive on the left-hand side on a dual carriageway, only entering lanes to the right to overtake, or for turning right. Don’t be fooled into thinking the lane on the left is the ‘slow lane’. There is no such thing.

A dual carriageway, unless signage says otherwise, is set at the national speed limit. This means regardless of which lane you or other drivers are in, the limit is 70mph. If a vehicle in the right lane is doing more, they are breaking the speed limit; they are not using the ‘fast lane’.


There are exceptions of course, and this is where paying attention to road markings is of utmost importance. Let’s take the obvious first; hard shoulders.

Unless signage says otherwise (such as in the case of an accident, roadworks or smart highway) the hard shoulder should never be driven in. And no, if you need a rest or to go to the toilet, you cannot pull into the hard shoulder; you should find the next rest area or services.

The hard shoulder is on the left of the road, but road markings will provide the clue you need to be aware of their presence. There will be a solid white line, which means ‘do not enter’. Similar lanes to the left which you should not enter include cycle lanes, bus lanes, and high-occupancy lanes.

Lane splitting

Another scenario where driving in the furthest lane to the left isn’t correct is when the road is splitting. A dual carriageway may split into more than two lanes, or the two lanes may split into two different roads, despite no physical barrier.

Road markings and signs will let you know which lane to get into; you will either remain in lane if staying on the road or choose to move to the left or right to enter a new road. It completely depends on your destination.

As a new driver, it is worth checking a map before you set off, so you aren’t reacting on the fly in these sorts of situations.

As you can see, there are a few exceptions to the rule of staying left. But in general, you should always be in the left-hand lane, for the majority of the time.

You are perfectly within your rights and the rules to enter lanes to the right if overtaking, or if taking a right turn. Just make sure not to go past the set speed limit.

For more information on dual carriageways and which lane to be in, check sections 133 to 143 of the Highway Code.

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