What phenomenon occurs when tires ride on a thin film of water?

The correct answer is hydroplaning, which occurs when a vehicle's tires lose contact with the road surface and ride on a layer of water instead. This happens when there is an excess of water on the roadway that creates a separation between the tire and the asphalt. As the water builds up, the tires are unable to displace it fast enough, resulting in a loss of traction. This can lead to a loss of steering control and an increased risk of accidents.

Understanding hydroplaning is crucial for safe driving because it can happen at relatively low speeds and often without warning. Drivers should be aware of weather conditions and adjust their speed accordingly, as well as ensure their tires are properly maintained with sufficient tread depth to help mitigate the risk of hydroplaning in wet conditions.