The Foolproof Guide to UK Road Sign Shapes, Colours and Meanings

Understanding UK road signs is not only important for passing your theory test, but essential for safe and responsible driving. Knowing what each sign means helps road users confidently navigate and respond appropriately to changing conditions. In this article, we discuss the shapes and colours of common road signs and what they mean.

Circles

Circles give orders. A simple way to remember this is to think of the circle as the letter O for order.

Blue Circles

Blue circles convey mandatory (or positive) instructions. They tell you to drive in a particular direction, such as ‘turn left’. They denote the minimum speed limit for a road. They also indicate that a route is exclusively accessible to specific categories of traffic, such as bicycles.

To help you remember what blue circle road signs are for, we've written a short and easy-to-remember poem.

The Blue Circle Road Sign Poem 

A positive instruction you must heed.

A blue circle denotes the minimum speed.

Or only depicted traffic CAN proceed.

Red Circles

Red circles convey prohibitive instructions. They tell you that you are not allowed to drive in a particular direction, such as ‘no left turn’. If you're not allowed to drive in a certain direction, there will be a red diagonal line across the sign. Red circles denote the maximum speed limit for a road. They also indicate that a route is not accessible to specific categories of traffic, such as bicycles.

To help you remember what red circle road signs are for, we've written a short and easy-to-remember poem.

The Red Circle Road Sign Poem 

A prohibitive instruction you must heed.

A red circle denotes the maximum speed.

Or depicted traffic CANNOT proceed.

Triangles

Triangles are warning signs. They alert drivers to potential hazards e.g. wild animals or changes in road conditions ahead e.g. the end of a dual carriageway. Here’s a handy trick to help you remember this. Bring the tips of your index fingers together and the tips of your thumbs together to form a triangle shape. Then, move your index fingers apart and gently shift your thumbs while keeping them touching to form the letter 'W', symbolising warning.

Rectangles

Rectangles provide information. A useful way to remember this is to rotate the horizontal rectangle by 90 degrees in your head, and then imagine the resulting vertical rectangle to be the letter “I” for information.

Blue Rectangles

Blue rectangles provide information, but on motorways, they give directions. Motorway signs tell you the distance (in miles) to a particular exit, the destination of the exit, and the corresponding junction number for that exit. The junction number is written inside a black box, in white text.

Green Rectangles

Dark green rectangles are used for direction signs on primary routes (major roads). Non‑motorway roads are called 'all‑purpose roads'. Roads of national and regional importance are called primary routes and are always identified by 'A' numbers. The route number on a primary route sign is written in yellow.

White Rectangles

White rectangles are used for direction signs on non-primary routes (minor roads). They are also used in combination with warning and regulatory signs to provide further information.

Diamonds

Diamond-shaped traffic signs instruct tram drivers.

Brown

Brown road signs guide drivers to a variety of destinations, including tourist attractions such as theme parks and zoos. Heritage sites like historic buildings, points of interest such as museums and galleries, as well as facilities such as hotels, guesthouses, camping grounds, and picnic sites.

Yellow

Regulatory yellow road signs provide instructions relating to parking, waiting, or loading. Yellow road signs are also used to indicate temporary conditions such as roadworks or traffic diversions.

There are four black shapes placed on a yellow background which are used for emergency diversion routes. The shapes are square, diamond, circle and triangle. The shapes can be filled in or outlined, as a result there are a total of eight unique symbols for emergency diversion routes. Emergency diversion route symbols can be followed on local road signs. They provide an alternative route to help drivers avoid congestion and re-join the motorway at the next junction in the event of an emergency.

Exceptional Signs

There are several exceptions to the standard shape and colour guidelines for traffic signs. These exceptions are implemented to improve the visibility and importance of those particular signs.

Octagon

The stop sign is the only octagonal road sign in the UK and can be easily identified even when it’s covered in snow. It means you must come to a complete stop and give way. You should wait until you can enter the main road without causing other drivers to change their speed or direction. Even if the way is clear, you are legally required to come to a complete stop before proceeding.

Upside-Down Triangles

An upside-down triangle with the words 'GIVE WAY' written inside means you must give way to traffic on the main road. You should wait until you can enter the main road without causing drivers already on the major road to change their speed or direction.

An empty upside-down triangle (with no words written inside) is accompanied by a white rectangular text plate, warning you of the distance (in yards) to a 'Give Way' sign or a 'Stop' sign.

A White Circle with a Black Diagonal Line

A white circle with a black diagonal line means the national speed limit for that particular type of road applies.

In England, Scotland, and Northern Ireland, the national speed limit for cars, motorcycles, and vehicles towing caravans or trailers in built-up areas is 30 mph. It is common to see maximum speed limit signs displayed in built-up areas, although the absence of any speed-limit signs on a road that has street lighting signifies that the 30 mph national speed limit applies.

The national speed limit for cars and motorcycles on a dual carriageway or motorway is 70 mph and 60 mph for a single carriageway road. The speed limit for these roads is reduced by 10 mph for cars towing a trailer or caravan. Hence, the national speed limit for cars towing a trailer or caravan is 50 mph for a single carriageway and 60 mph for a dual carriageway or motorway.