What condition makes driving most dangerous in terms of weather?

Driving conditions after the first rain following a prolonged dry spell are particularly dangerous due to the oils and debris that accumulate on the road surface during the dry period. When rain first begins to fall, this mixture creates a slippery surface, significantly reducing traction for vehicles. This phenomenon is often referred to as "slick" conditions, which can lead to an increased likelihood of skidding and loss of control, especially for those who are not accustomed to these conditions.

Other weather conditions such as heavy fog, snowy conditions, and high winds also present their own hazards, but the specific nature of the first rain on a dry road renders it uniquely treacherous. The combination of reduced visibility in fog or the challenges of snow and ice can be extreme, but the initial rain's effect on road surfaces and vehicle control amplifies the risk more immediately, as it can catch drivers off guard when transitioning from dry to wet conditions.