Which is a key factor in determining when to pass another vehicle?

Passing another vehicle safely requires a clear assessment of the road conditions ahead. The clarity of vision ahead is crucial because it allows the driver to identify potential hazards, oncoming traffic, or changes in road conditions that may affect the safety of the maneuver. A clear line of sight ensures that the driver can judge whether there is enough time and space to complete the pass without risk of collision.

When visibility is limited, making a decision to pass can be dangerous. It may lead to situations where the driver cannot react appropriately to oncoming vehicles or obstacles in the road. Therefore, ensuring that the path ahead is clear not only promotes safety but also aligns with traffic laws and best driving practices.

The other factors, while relevant to driving in general, do not directly address the immediate concern of safety when passing another vehicle. Engine efficiency and driver skill, though important, do not compensate for the lack of visibility that could endanger the driver and others on the road. Thus, the clarity of vision ahead stands out as the most critical factor in determining the right moment to pass another vehicle.