overtaking or turning right
You should normally use the left-hand lane on any dual carriageway unless you are overtaking or turning right. When overtaking on a dual carriageway, look for vehicles ahead that are turning right. They’re likely to be slowing or stopped. You need to see them in good time so that you can take appropriate action.
B overtaking only, never turning right
C fast-moving traffic only
D turning right only, never overtaking