Motorway Studs

To make sure that driving on the motorway is safe during the hours of darkness, or in periods of low visibility, there are motorway studs fitted into the road to assist you to identify and remain in the correct lane and to help guide you off the motorway when you need to.

Also known as ‘cat’s eyes’, thanks to their likeness to a set of cat’s eyes looking at you on the road, these reflective studs come in different colours which each have specific meanings to guide you safely to your destination.

It can be easy to forgo motorway studs in your driving theory revision as you won’t have driven on the motorway before, but don’t let reflective studs catch you out on your theory test or, more importantly, in practice. In this article, we will talk about what the different colour motorway studs mean and everything you need to know to drive safely and to get you through this section of your theory test.

Motorway Stud Colours

There are five different kinds of motorway studs: white, amber, red, green and fluorescent green/yellow. The meaning of these studs are unchangeable so once you have learnt their meanings you can be confident of your position on the motorway.


In your driving theory test, you may be asked the question: what colour are the reflective studs between a motorway and its slip road? The answer to this question is: green. When there is a slip road, either on or off the motorway, the reflective studs will be green so that you are aware of these junctions when visibility is poor or if it is dark. This will ensure you can identify the route you need to take off the motorway and be aware when traffic is joining the motorway.


Red reflective studs can be found at the left-hand side of the motorway, in between the lane and the hard shoulder. These are there to make sure you don’t veer out of the left-hand lane into either the hard shoulder or side of the motorway if there is no hard shoulder. Red studs will help you to stay in the left lane if you are driving in the dark or on a misty day.


You will find amber coloured reflective studs on the right-hand side of the motorway, next to the central reservation. The intention of the amber studs is to keep you in the right-hand lane and away from the central reservation when the conditions are making it difficult for you to see this.


White studs are placed in between the lanes on a motorway to help keep you in lane. These work by reflecting the light from your headlights back to you so that you are able to distinguish the different lanes on the motorway if you are caught in a heavy downpour, or you are required to drive late at night.

Fluorescent Green and Yellow Studs

Make sure you are aware of the purpose of green and yellow fluorescent studs on the motorway. This could easily catch you out on your theory test as this motorway stud colour is less common. The purpose of green/yellow studs is to notify drivers of potential adjustments to the road layout due to their being roadworks taking place on the motorway.

Learning Motorway Reflective Studs

Now you know what each of the different coloured reflective studs mean, you need to be able to remember these for your driving theory test. Questions about motorway driving, including the specific purpose of individual reflective studs, are common in the theory test so make sure you are clued up on your motorway theory.

A good way of remembering what the purpose of the green, red, amber, white and fluorescent green/yellow studs are is to draw out a motorway layout and use some coloured pens to indicate where each of the studs are in the road layout. This will help you to memorise the meaning of the colours, and the practice of drawing it out will help you to visualise their position on the motorway if you are asked about this in the theory test. Don’t worry if you don’t like drawing or you aren’t artistic – some simple straight lines and dots are all you need!

Quick Reference Guide to Colours of Motorway Studs

To recap, below is a quick reference guide containing the keywords in bold that you need to associate with each colour in order to remember their meaning:

Green: Indicates a slip road off and on the motorway

Red: Left-hand side of motorway, in between the left-hand lane and hard shoulder

Amber: Right-hand side of motorway, in between right-hand lane and central reservation

White: Indicates the lanes on the motorway.

Fluorescent green/yellow: Indicates changes to the motorway layout caused by roadworks


Making sure you are clued up on the meaning of motorway studs is essential when preparing for your driving theory test, and to ensure you are well-prepared for after you have passed your practical test and start to drive on the motorway.

The key things to remember are that motorway studs, also known as ‘cat’s eyes, are fitted into the road to make sure it is safe to drive on the motorway both when the weather turns for the worse causing low visibility, and during the hours of darkness. It is likely that you will be asked a question about where on the motorway a specific coloured reflective stud can be found, so making sure you know these will gain you some important marks to help you pass the theory test.

One method of memorising the location of each of the reflective studs is to draw out a simple motorway layout and use some coloured pens to indicate where each of the motorway studs should be. You can also use keyword association like in the quick reference guide above to help you to distinguish between the colours. Happy memorising and we wish you the best of luck!