What is the purpose of regulatory signs?

Regulatory signs are designed to communicate important traffic regulations that drivers must follow to ensure the safety and flow of traffic. These signs typically include prohibitory signs, which indicate actions that are not allowed (such as "No U-Turn" or "Do Not Enter"), as well as signs that require specific actions or designate rules (such as "Yield" or "Stop").

The purpose of regulatory signs goes beyond merely indicating speed limits or pedestrian crossings. While some regulatory signs do focus on speed limits, their primary function extends to encompassing a wide range of traffic regulations applicable to vehicle operators. Therefore, the correct answer highlights the comprehensive role of regulatory signs in managing traffic behavior and ensuring adherence to traffic laws, hence providing the necessary guidance for safe driving practices.