On cold, wet days, shade from trees or buildings can hide spots of ice. These areas freeze first and dry out last. Bridges and overpasses can also hide spots of ice. They tend to freeze before the rest of the road does. If it starts to rain on a hot day, pavement can be very slippery for the first few minutes.
Heat causes oil in the asphalt to come to the surface.
It makes the road slippery until the oil is washed off. Close to the freezing point, the road is icy and may be more slippery than at colder temperatures. Driving In Traffic Drive slower when there are many vehicles close together on the road. Otherwise stopping safely will be harder because you have less room. Drive slower so you can stop in the distance you have.