What action is required before overtaking a vehicle on a two-lane road?

Before overtaking a vehicle on a two-lane road, it is essential to ensure the lane ahead is clear. This is critical for safety since you need to be certain that there are no oncoming vehicles, obstacles, or other hazards that could create a dangerous situation while you are attempting to pass. This action allows the driver to safely maneuver around the vehicle without the risk of a collision.

On the other hand, passing at a high speed can be very dangerous and increases the likelihood of an accident due to reduced reaction time. Waiting for a traffic signal is not applicable on a two-lane road, as signals do not govern lane changes or passing unless at an intersection. Finally, slowing down and observing traffic can be beneficial but does not directly address the necessity of ensuring the lane ahead is clear before making a passing maneuver. Therefore, ensuring the lane is clear is the most critical step in overtaking safely.