How is a railroad warning sign visually represented?

A railroad warning sign is characterized by a yellow circle with a black outline. This distinctive design is used to alert drivers to the potential hazard of an approaching railroad crossing. The use of a yellow background signifies caution, indicating that drivers should be aware of the possibility of trains crossing and take appropriate safety measures.

The choice of a circular shape is also significant, as it is universally recognized to convey specific instructions or warnings. This visual representation helps ensure that the warning sign captures the attention of approaching drivers, allowing them to react in a timely manner to ensure safety at railroad crossings.