What does a yellow diamond-shaped sign indicate?

A yellow diamond-shaped sign is specifically designed to alert drivers to potential hazards or changes in road conditions ahead. These signs are standard in traffic control and are widely used to convey that the driver should exercise caution due to various scenarios, such as curves in the road, school zones, or animal crossings. The color yellow is used for these signs because it is highly visible and emphasizes the need for attention and caution.

The other options serve different purposes: speed limit signs indicate the maximum legal speed, signs providing information about rest areas help drivers find places to stop and rest, and signs related to yielding to pedestrians specifically instruct drivers on right-of-way rules at crosswalks. Each of these has a distinct shape and color associated with its specific function, making them easily distinguishable from warning signs like those indicated by the yellow diamond shape.