What does the MUTCD define white signs as?

The Manual on Uniform Traffic Control Devices (MUTCD) specifies that white signs are used primarily for regulation. This means that any instructions, restrictions, or requirements for road users are conveyed through these signs. For instance, regulatory signs such as speed limits, parking regulations, and no-entry signs are typically white, clearly indicating the rules that drivers must follow. This color coding helps ensure consistency and clarity in communication on the roads, helping to maintain safety and order.

In this context, other options refer to different types of signs. For example, warning signs typically use yellow, guidance signs may use green or blue, and information signs might involve other colors. Thus, understanding the role and meaning of white signs is crucial for interpreting traffic regulations correctly.