Which of the following is an indicator that you should not pass another vehicle?

When approaching a hill or curve, it is crucial to avoid passing another vehicle because visibility is significantly reduced in these scenarios. The driver may not be able to see oncoming traffic or any potential hazards that could pose a danger during the passing maneuver. On a hill, the road may rise sharply, obscuring the view of vehicles coming from the opposite direction. Similarly, on a curve, the same visibility issues arise, making it difficult to gauge whether it is safe to pass. Therefore, these situations require extra caution and typically indicate that passing is not safe.

In contrast, rural areas, daylight hours, and clear weather conditions do not inherently provide a valid reason to pass; safety depends on road layout and visibility rather than just the environment.