Reflective road studs: what they mean
Reflective road studs mark lanes and road edges. White, red, amber and green show different parts of the road.
What do reflective road studs mean?
Reflective road studs help you identify lanes and road edges. Rule 132 explains the colours: white marks lanes or the road centre, red marks the left edge, and amber marks the central reservation. Green marks the main carriageway edge at lay-bys and slip roads.
Know your traffic signs says coloured studs help at night, especially on wet roads, or when visibility is poor.
Quick quiz
What does the picture at the top of this page show?
- Bars that count down to a motorway exit.
- Coloured studs mark lanes and road edges.
- Long white dashes warn of a hazard ahead.
Show answer
B. Coloured studs mark lanes and road edges. The colours identify lanes, the left edge, the central reservation and the edges at lay-bys and slip roads (The Highway Code, rule 132). Source: Know your traffic signs: road markings, GOV.UK; The Highway Code, rule 132, GOV.UK
Where will you see it?
Along traffic lanes and road edges, including beside the central reservation of a motorway or dual carriageway. Green studs mark lay-bys and slip road entrances and exits.
What should you do?
Use the colours to identify the lanes and road edges, especially at night or in poor visibility.
What do people get wrong?
Mixing up red and amber studs puts the road edges the wrong way round. Red marks the left edge; amber marks the central reservation.
Common questions
What do green road studs mean?
Rule 132 says green studs mark the edge of the main carriageway at lay-bys and slip roads.
What colour are road studs beside the central reservation?
Amber. Rule 132 says amber studs mark the central reservation of a dual carriageway or motorway.
Compare with
Hazard warning lineLong white dashes warn of a hazard ahead.
Double white linesThe line nearer to you decides if you may cross.
Want to test someone else? Play a road-sign quiz with friends and family.
Sources
Checked on 5 November 2026 against Know your traffic signs (road markings) and The Highway Code rule 132.
Contains public sector information licensed under the Open Government Licence v3.0. The diagram is our own simplified drawing, not to scale. Sources and image credits.