Final answer:
A cautionary road sign with a yellow diamond shape and an arrow pointing in opposite directions indicates two-way traffic ahead. It warns drivers to be prepared for traffic coming from both directions.
Step-by-step explanation:
In the context of road signs, a yellow diamond shape with an arrow pointing in opposite directions indicates a cautionary sign indicating two-way traffic ahead. This sign is commonly seen in areas where a road changes from one-way traffic to two-way traffic or where a divided road ends. It warns drivers to be cautious and prepared for traffic coming from both directions.