At what point are roads likely to be especially slick?

Roads are particularly slick just after it begins to rain or drizzle due to the combination of water and the oils, dust, and debris that have accumulated on the surface of the road. When rain first begins, it mixes with these substances, creating a slippery film that can make driving hazardous. This condition is often more dangerous than during steady rainfall, as the first few moments can catch drivers off guard.

As the rain continues, the water can wash away some of these contaminants, thereby reducing slickness. However, the initial few moments of rain pose a greater risk due to this hazardous mixture on the road.