Why is it necessary to increase clearance time when passing uphill?

Increasing clearance time when passing uphill is necessary primarily because vehicles descending the hill may be traveling at higher speeds. This can create a situation where the driver attempting to pass does not have enough time to complete the maneuver safely. The increased speed of downhill vehicles, whether due to gravity or their inability to brake quickly when going downhill, necessitates a greater clearance time to ensure there is enough space and time to avoid potential collisions.

In passing situations, timing and distance become critical factors, especially on inclines where visibility can be limited and reactions need to be swift. The correct answer emphasizes the importance of awareness about the speed of other vehicles in the area, particularly those coming downhill, which reinforces safe driving practices while navigating such challenging terrains. Consequently, ensuring adequate clearance not only promotes safety but also enhances driving efficiency and reduces the risk of accidents.