What shape and color are regulatory signs typically?

Regulatory signs are designed to inform drivers of laws and regulations that must be obeyed on the road. Typically, these signs are round and feature a red background with a white interior. The red color indicates a prohibition or command, which is essential for maintaining safe and orderly traffic flow. The round shape is specifically used for signs that give vital instructions, such as speed limits or other rules that drivers must adhere to.

This design choice ensures that these signs are easily recognizable and quickly understood by drivers, which helps reinforce compliance with the rules of the road. Other shapes and colors are used for different types of signs, such as warning or informational signs, but the round and red design is distinctive and consistent for regulatory signs.