Which condition makes roadways most slippery?

Which condition makes roadways most slippery?

• A. The middle of a heavy rain
• B. Heavy rain
• C. The first rain after a dry spell
• D. Ice

Answer: (C)

Road surfaces can be unusually slick when a long dry spell ends and rain first begins. During dry periods, oil, gasoline residue, and grime accumulate on the pavement. When the first rain falls, that film mixes with the water and creates a very slick layer, making traction notably poor. As rain continues, the film is gradually washed away, and the surface becomes less slippery. While ice is extremely slippery, the scenario described highlights the initial rain after a dry spell, where the oil-and-water film ramps up slipperiness more than during ongoing rainfall or during a dry stretch.

Road surfaces can be unusually slick when a long dry spell ends and rain first begins. During dry periods, oil, gasoline residue, and grime accumulate on the pavement. When the first rain falls, that film mixes with the water and creates a very slick layer, making traction notably poor. As rain continues, the film is gradually washed away, and the surface becomes less slippery. While ice is extremely slippery, the scenario described highlights the initial rain after a dry spell, where the oil-and-water film ramps up slipperiness more than during ongoing rainfall or during a dry stretch.