When is a rain-slick surface considered most slippery?

A rain-slick surface is considered most slippery right after it begins to rain due to the accumulation of oil and debris on the road. When rain starts, it mixes with these substances, creating a very slick film on the surface. The initial moments of rainfall can lift the oils that have settled on the pavement, which subsequently leads to a drastic reduction in traction for vehicles, including motorcycles.

This situation can pose significant hazards for riders, as their tires may struggle to grip the road under these conditions. Once the rain continues for a while, the water washes away much of the oil and debris, and while surfaces still remain wet, they become less slippery compared to that initial phase. Hence, understanding that the most dangerous time for traction loss on a rainy day is right at the beginning of rainfall can help motorcyclists take necessary precautions.