What is the difference between a dual carriageway and a motorway?

Not sure what the difference between a dual carriageway and a motorway is? Here’s everything you need to know.

If you’re learning to drive, it’s important to understand the difference between certain types of roads – and the most common ones you’ll come across are dual carriageways and motorways.

Many drivers assume that the main difference between the two is simply the number of lanes, but it’s much more complex than that. This handy guide will explain the differences between a dual carriageway and a motorway to help you become a safer and more informed driver.

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What is a dual carriageway?

A dual carriageway is a type of road where traffic travelling in opposite directions is separated by a central reservation or barrier. The term “dual” refers to the two separate carriageways – not the number of lanes. This means a dual carriageway can have just one lane in each direction, as long as there’s a physical divider splitting the traffic.

These roads are built to handle higher traffic volumes and typically allow for higher speeds than single carriageways. They’re also designed to improve safety by reducing the risk of head-on collisions.

Examples of dual carriageways in the UK include huge parts of the A1 heading up to Edinburgh and the A38 Devon Expressway.

What is a motorway?

A motorway is a high-speed road specifically designed for fast-moving traffic and to carry large volumes of vehicles safely and efficiently.

Motorways typically have two to three lanes in each direction (sometimes more), giving you space to overtake and maintain steady speeds. They also have controlled entry and exit points, with no traffic lights, roundabouts, or pedestrian crossings.

Examples of major UK motorways include the M1, the M25, and the M6.

What are the differences between a dual carriageway and a motorway?

Knowing whether you’re on a motorway or a dual carriageway helps you drive safely, follow the rules, and plan your journey. Here are some key differences you need to know about:

Lane numbers and road design

Motorways are usually wider and built to higher standards, often with three or more lanes, long merge areas, and smoother layouts for high-speed travel. Meanwhile, dual carriageways can vary more in lane numbers and can feel less predictable, with more junctions and access points.

Access and junctions

Motorways have controlled entry and exit via slip roads, with no traffic lights or direct access to properties. Dual carriageways often feature roundabouts, traffic lights, and side-rise connections. This means you need to stay alert for stopping or turning vehicles.

Speed and purpose

Motorways are designed for long distance, fast travel, carrying high traffic volumes safely at speeds up to 70mph. Dual carriageways support a mix of local and longer journeys, and speeds can vary due to junctions or crossing traffic.

Safety features

Motorways include hard shoulders, longer slip roads, and fewer interruptions, reducing the risk of an accident. Dual carriageways may lack these features and usually involve more interaction with other road users.

Who can drive on them

Motorways restrict pedestrians, cyclists, horse riders, and some learner motorcyclists under the Highway Code. Dual carriageways generally allow a wider range of vehicles, unless signs indicate otherwise.

Road signs

Motorway signs are blue, while dual carriageway signs are green. This makes it easier for you to know what kind of road you’re on and what rules apply.

What are the similarities between a dual carriageway and a motorway?

Yes, motorways and dual carriageways have distinct differences, but they also share several similarities that are important for you to know. These include:

• Both dual carriageways and motorways usually have two or more lanes in each direction. This helps traffic flow smoothly and makes overtaking safer.
• Both types of road feature a central barrier that separates traffic moving in opposite directions, reducing the risk of head-on collisions.
• Cars on both motorways and dual carriageways generally follow the national speed limit of 70mph (unless signs indicate otherwise), making it easy to know the safe maximum speed.
• Both roads use clear, standardised road signs to guide drivers, show upcoming junctions, and warn of any restrictions.
• Markings on both road types help drivers stay in their lanes, prepare for upcoming junctions, and navigate changes in road layout safely.

Dual carriageway vs motorway FAQs

Are motorways and dual carriageways the same?

No. While many motorways are dual carriageways, not all dual carriageways are motorways. Motorways have stricter rules, controlled access, and higher design standards, whereas dual carriageways can be more variable in layout and usage.

How to tell the difference between dual carriageway and motorway

The best way to tell the difference between a motorway and a dual carriage is by its sign colours (blue for motorways, green/white for dual carriageways), the presence of hard shoulders, and vehicle restrictions. Motorways are also designated with an ‘M’ in the sign, for example, M1.

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