what colour are the reflective studs between the lanes on a motorway

The reflective studs between the lanes on a motorway are white. These white studs help to mark the separation between lanes on motorways, reflecting the light from vehicle headlights to aid visibility in poor weather or low light conditions. Other colored studs have different meanings: red studs mark the left edge of the motorway or the hard shoulder, amber studs mark the central reservation, and green studs are used to indicate slip roads (entrance or exit lanes) on the motorway.