Which of the following indicates a safe passing opportunity?

A straight road with good visibility is the optimal scenario for a safe passing opportunity. This environment allows drivers to see oncoming traffic clearly and assess whether there is enough time and space to safely overtake another vehicle. Good visibility is crucial because it enables drivers to judge the distance and speed of approaching vehicles, reducing the likelihood of a collision.

In contrast, a road with a lot of traffic creates a riskier passing situation, as it may not provide the necessary space or time to perform the maneuver safely. A road lacking signage can often indicate unclear rules or conditions, making it difficult for drivers to determine if passing is safe or legal. Lastly, a sharp curve in the roadway significantly limits visibility and increases the chance of encountering oncoming traffic unexpectedly, making it a hazardous choice for passing.