How are directional signs typically color-coded?

Directional signs are typically color-coded with black letters on a white background to ensure maximum visibility and readability. This combination provides a significant contrast, making it easy for individuals to quickly interpret information from a distance. Black is a bold color that stands out against white, which is a neutral background. This enhances the effectiveness of the signs, especially in various lighting conditions and environments, including both day and night.

The other options do not align with standard practices for directional signage, which prioritize clarity and accessibility. For instance, red on yellow is often associated with warning signs, while blue and green combinations are less common for directional purposes. Understanding these color conventions is crucial in maintaining a consistent and effective communication system within air operations and other navigational contexts.