When are roadways typically the most slippery?

Roadways are typically the most slippery when it first starts raining due to the combination of oil, dirt, and other debris on the road surface that gets mixed with the rainwater. Initially, this mixture creates a slick and hazardous driving condition. The first few minutes of rain are particularly problematic because the rain has not yet fully washed away the accumulated oils and contaminants, making the pavement extremely slippery for vehicles.

As the rain continues, those materials are washed away, and while the road can still remain slippery, the hazards tend to diminish. This phenomenon is crucial for drivers to keep in mind, as the initial moments of rain can pose significant risks for losing traction and control of the vehicle.