How can you tell a road is slippery in wet conditions?

Identifying a slippery road in wet conditions is crucial for safe driving. The correct option describes how looking for dark patches or a shiny appearance on the road surface can indicate that the road is slick. When rain falls on certain types of asphalt, it can wash away dirt and oil, forming a slippery layer that is often visible as dark patches.

A shiny surface results from water mixing with oils and debris, creating a highly slippery condition. Drivers should be particularly cautious when they see these shiny areas, as they can lead to reduced traction and increase the risk of losing control of the vehicle.

The other options do not provide reliable indicators of a slippery road. For instance, while the sound of tires could vary due to road conditions, it is not a consistent or clear sign of slipperiness. The presence or absence of potholes has little impact on the slickness of the road surface during rain, and the amount of traffic does not necessarily correlate with road conditions.