Why is pavement often slippery for the first few minutes of rain on a hot day?

Why is pavement often slippery for the first few minutes of rain on a hot day?

• A. Oil on the asphalt due to heat rising to the surface
• B. Water on the road
• C. Ice forms on the surface
• D. Loose gravel on pavement

Answer: (A)

Hot pavement pushes the oily binder of the asphalt to the surface, forming a very thin film. When rain begins on that hot surface, water sits on top of this oily layer and creates a slick that drastically reduces tire grip, making the road feel slippery for the first few minutes. As the rain continues, the oil is diluted and washed away, and traction returns. The other ideas don’t fit the situation as well: water alone on dry pavement isn’t the same kind of slippery film, ice would only form at freezing temperatures, and loose gravel isn’t the consistent slick patch you feel right after rain on a hot day.

Hot pavement pushes the oily binder of the asphalt to the surface, forming a very thin film. When rain begins on that hot surface, water sits on top of this oily layer and creates a slick that drastically reduces tire grip, making the road feel slippery for the first few minutes. As the rain continues, the oil is diluted and washed away, and traction returns. The other ideas don’t fit the situation as well: water alone on dry pavement isn’t the same kind of slippery film, ice would only form at freezing temperatures, and loose gravel isn’t the consistent slick patch you feel right after rain on a hot day.