When are road conditions most dangerous in winter?

The most dangerous road conditions in winter occur during the first few minutes of rainfall after a dry spell due to the presence of oil and debris that has accumulated on the roadway. When rain begins to fall, it can mix with this oil, creating a slick, slippery surface that significantly reduces traction for vehicles. This reduced traction can lead to an increased likelihood of skidding or losing control of the vehicle.

In contrast, heavy snowstorms can be hazardous, but road maintenance typically responds to snow conditions with plowing and salting, which can help improve traction over time. Temperatures above freezing can also lead to melting snow and ice, but when they drop again, they can create black ice, which is hazardous but not as immediately dangerous as the conditions created by the initial rain. Early morning hours can present challenges due to low visibility or potential icy patches, but the most acute risks come right at the start of rainfall after prolonged dry conditions due to the slick surface.