Final answer:
A single white line at the entrance of an intersection commands vehicles to stop or yield before entering the intersection.
Step-by-step explanation:
A single white line at the entrance of an intersection commands vehicles to stop or yield before entering the intersection. This line is used to control the flow of traffic and ensure safety. It is commonly used in road traffic management systems to regulate the right of way and prevent accidents.
For example, when you see a single white line at the entrance of an intersection, it means that the vehicles approaching the intersection should yield to vehicles already in the intersection or stop completely before entering, depending on the specific traffic rules of the area.