Side road junction from the right

W108

Where: On any road before you reach the place where another road joins your road from the left (W107)(TW107) or from the right (W108)(TW108).
Purpose: To warn that traffic may be approaching you from the left or right-hand side.
Action: Slow down so that you will be able to stop, or go around the corner or pass the intersection at a safe speed. Look out for other traffic at the intersection that might not yield. Version 1.00 23 Jun 2012 Copyright © 2012 by SA Department of Transport

Manual on Road Traffic Signs, page 24.