What is the primary purpose of a stop sign?

The primary purpose of a stop sign is to require drivers to come to a complete stop. This regulation is essential for ensuring safety at intersections where visibility may be limited or where vehicles, cyclists, and pedestrians are sharing the road. When drivers see a stop sign, it indicates that they must halt their vehicle fully before proceeding, allowing them to assess the intersection for any oncoming traffic or pedestrians. This stopping rule is designed to prevent accidents and maintain orderly traffic flow by giving all road users the opportunity to proceed safely.

While slowing down traffic is important at stop signs, it is not the sole or primary purpose. Similarly, indicating the end of a highway or giving priority to vehicles on the left are not relevant functions of a stop sign and pertain to different traffic control measures. The definitive requirement to stop is what distinguishes the stop sign from other traffic signs, solidifying its crucial role in road safety.