Washington State Department of Licensing Knowledge Test

What condition is likely to cause hydroplaning?

1. Sunny weather

2. Heavy wind

3. When it is raining

4. Cold temperatures

The correct answer is: When it is raining

Hydroplaning occurs when a vehicle's tires lose contact with the road surface and instead ride on a layer of water. This loss of traction can happen when it is raining because rain creates puddles on the road that can interfere with tire grip. When water accumulates, especially during heavy rainfall, the tires' ability to channel the water away decreases, resulting in a loss of control. In contrast, sunny weather does not create conditions conducive to hydroplaning, as the roads tend to be dry. Heavy wind can affect vehicle stability and steering but is not a direct cause of hydroplaning. Cold temperatures can lead to frozen road conditions, which are different from the wet conditions that cause hydroplaning. Therefore, raining is the most critical factor influencing the likelihood of hydroplaning, particularly if there is a significant amount of water on the road.