Which two colors are classified as undesignated sign colors?

Undesignated sign colors refer to colors that are not specifically associated with standard regulatory, warning, or guide signs as established by traffic control device guidelines. Coral and light blue are not designated for any particular use.

In the context of traffic signage, recognized colors serve specific purposes: for instance, red is typically used for stop or prohibition signs, while yellow is often employed for caution signs. Similarly, blue is used for services, and brown for recreational or cultural interests. Hence, coral and light blue stand out as colors without a defined role, allowing flexibility in their potential applications outside of traditional traffic control signage. This classification contributes to the understanding of sign colors and their associated meanings within the realm of traffic management and communication.