Which of the following signs would most likely indicate a road curve ahead?

Advance warning signs are specifically designed to alert drivers about impending changes in the roadway or conditions ahead, allowing them to prepare for those changes. A sign indicating a road curve ahead falls into this category, as it provides an early warning that drivers need to adjust their speed and driving behavior when approaching a curve.

These signs typically have distinctive shapes and colors, such as yellow with black symbols, which makes them easy for drivers to recognize and react to in a timely manner. Their purpose is to enhance safety by informing motorists well in advance of any potential hazards or necessary adjustments in driving.

Other types of signs, such as regulatory signs, focus on laws and regulations (like speed limits or stop signs), traffic control devices help regulate and control traffic flow, and service signs provide information about services available along the roadside. While all these signs serve important functions, it is the advance warning signs that are specifically tailored to notify drivers of road conditions like curves, enabling them to drive safely.