Hazard road signs can indicate the direction of the road or the end of a road (e.g. at a T-intersection), usually with black chevrons on a white or yellow background. They may also give an indicated safe speed for a corner in dry weather.
They may be used to draw attention to an obstruction or direct traffic around it. There are other temporary road signs which feature chevrons and they will be covered in the temporary road signs article.
Here are the hazard road signs in Australia.