What does the "Do Not Pass" sign indicate?

The "Do Not Pass" sign indicates that drivers are prohibited from passing other vehicles on that specific stretch of road. This rule is often in place for safety reasons, typically in locations where visibility is limited, such as on hills or curves where the driver cannot see oncoming traffic. The sign serves as a precautionary measure to reduce the risk of collisions by warning that it is unsafe to change lanes or overtake slower vehicles. By ensuring compliance with this sign, drivers contribute to a safer driving environment for themselves and others on the road.

Other options misunderstand the implications of the sign. For instance, the idea that passing is allowed under all circumstances contradicts the very purpose of the sign. Similarly, the suggestion that only emergency vehicles may pass does not accurately reflect the general prohibition on all vehicles, while the notion that all vehicles must go slow is not aligned with the intent behind the sign, which is specifically focused on the act of passing.