Why are roads particularly slippery at the beginning of a rainfall?

• A. Water mixes with oil
• B. Rain washes away dirt and debris
• C. Drivers are not prepared for the rain
• D. Roads become too wet

Answer: (A)

Roads are particularly slippery at the beginning of rainfall primarily because water mixes with oil and other substances that have accumulated on the road surface, such as dirt, dust, and rubber from tires. When it first starts to rain, this mixture creates a slick film on the roadway. The oil on the road does not immediately wash away, and the combination of water and oil significantly reduces the grip of the tires on the pavement, making it easier for vehicles to skid and lose traction.

The other options do not directly address the immediate slippery conditions caused by the initial rain. While rain does wash away dirt and debris over time, it is not the main reason for the slipperiness at the onset of the rain. The statement about drivers not being prepared for rain touches on human factors, but does not explain the physical characteristics of the road itself. Lastly, while roads do become wet during rain, simply being wet does not inherently cause them to be slippery in the way that the interaction of water and oil does at the start of a rainfall.