Why are the first few minutes of a rainstorm considered most dangerous for drivers?

The first few minutes of a rainstorm are considered most dangerous for drivers primarily because the rain initially mixes with oil, dirt, and debris that have accumulated on the road surface. This mixture creates a slick layer that significantly reduces tire traction and can lead to loss of control over the vehicle. During the first few minutes of rain, this effect is particularly pronounced because the water has not yet fully washed away the oil and grime. Understanding this hazard is crucial for drivers, as it emphasizes the need for increased caution, reduced speed, and increased stopping distance immediately after rain begins. As the rain continues, the road conditions typically improve as the water helps to clear away the dirt and oil.