The **danger when overtaking** mainly depends on whether it is necessary to **enter the oncoming lane**. This is because when overtaking, especially on two-way roads, you may need to move into the opposite lane to pass the vehicle in front. This maneuver is dangerous because:

- **Limited visibility**: In situations such as curves, hill crests, fog, or heavy rain, visibility is reduced, making it difficult to see if a vehicle is coming from the opposite direction.

- **Space and time**: When entering the opposite lane, you need to ensure there is enough space and time to complete the overtaking without the risk of collision with oncoming vehicles.

- **Road conditions**: You must consider the speed and road conditions, as these affect the time and distance needed to overtake safely.

Therefore, the need to enter the opposite lane is a critical factor that increases the danger of the overtaking maneuver.