Which road surface is considered the slickest?

Dry ice is considered the slickest road surface due to its extremely low temperature and the unique properties it exhibits. When temperatures fall below freezing, the surface of the dry ice remains solid and can become very slick, making it difficult for vehicles to maintain traction. This is particularly hazardous for driving, as the surface does not provide enough friction for tires to grip.

In contrast, while wet asphalt can be slippery due to moisture, it generally provides more traction than dry ice. Freshly paved roads may also be slick, especially when new sealant is applied, but typically this condition does not last as long as that of dry ice. Loose gravel can pose its own challenges for traction but doesn’t create the same level of slickness as dry ice does. Thus, the extreme conditions and surface characteristics make dry ice the slickest of the choices presented.