PassSecondary Crossroad
Where: On the approach to a crossroad where the road you are travelling on is the lesser of the two — typically a side road meeting a through route.
Purpose: To warn of the crossroad ahead and to tell you that the crossing road has priority. The thick bar on the sign is the priority road, and here it runs across your path, not with it.
Action Required by Driver: Slow down well before the junction and be ready to stop. Traffic on the crossing road is not expecting to give way to you and may be travelling considerably faster. Look for a stop or yield sign at the junction itself and obey it — this warning sign prepares you for that control, it does not replace it.
The temporary version (TW103)
The same sign on a yellow face is the temporary one, used at road works, at a collision scene, or anywhere the normal arrangement of the junction has been changed. The symbol means exactly the same thing — the yellow tells you the situation is not permanent, so give it more attention rather than less.
Telling W102 and W103 apart
Only one detail separates them: which bar is thicker.
Thick bar across your path — secondary crossroad, you give way.
Thick bar in your direction of travel — priority crossroad, the other road gives way to you.