One way traffic: drive only in the indicated direction
Drive only in the indicated direction.
Where you will see it
Where a one way street bends or meets another, the arrow turned to show which way the flow now runs.
What to do
Follow the arrow through the change of direction and take the lane it points at early. There is no oncoming traffic on a one way street to remind you which way it runs, so the sign is the only thing that tells you.