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What are motorway reflective studs?

24th August 2023

Driving on the motorway is a must at some point for the majority of drivers, whether driving to go on holiday or just for the daily commute. This guide will explain what motorway reflective studs are and what they’re used for.  

What are reflective studs or cat’s eyes?

Otherwise known as cat’s eyes, due to the way they reflect light, reflective studs on the motorway are small devices embedded in the road surface of motorways, A and B roads and roundabouts. Cat’s eyes can come in different colours and are spaced out along the road. They consist of two pairs of reflective glass spheres in front of an aluminium mirror. They are housed in a rubber moulding and cast iron surround which means they sink below the surface of the road to avoid causing damage to your tyres when you drive over them.  

Why do motorways have reflective studs?

Cat’s eyes and studs are used to indicate certain elements drivers should be aware of including; 

  • Edge of the motorway lane 
  • Central reservation 
  • Lane changes  
  • Where you can drive 

They are important for the safety of drivers and road users, especially in areas with a high-speed limit. They are especially valuable for drivers at night, or during low visibility conditions like rain, fog, sleet and snow where lane markings may not be visible. 

Some motorway studs are designed as “rumble stripes” to alert motorway drivers when they need to slow down. 

What do the different colours of cat’s eyes mean? 

Cat’s eyes or reflective studs are usually colour coded in order to communicate specific information to drivers. The most common colours include:  

  • White studs: White studs are used to mark the lanes on the road in the same direction of the traffic flow.  
  • Red studs: Red studs usually indicate the left-hand edge of the road, where the boundary of the carriageway is. They are used as a visual guide to drivers in low light.  
  • Amber studs: Amber studs are usually placed between the lanes of a central reservation as a warning to drivers against upcoming exits, diversions or merging traffic.  
  • Green studs: Green studs are not often used, but can be used to indicate refuge areas or laybys. 
  • White studs with a white border: These studs indicate the hard shoulder and are placed to guide drivers from encroaching onto the hard shoulder. 
  • Red and white studs: Red and white studs are used together to indicate temporary lane changes, roadworks or incidents.  

Planning your next road trip? Remember to book a service at least every 10,000 miles to ensure your vehicle is running smoothly and safety. Locate your nearest Merityre garage to book in for your next service. Alternatively, contact our helpful team to find out more.