Iowa DOT Learner's Permit Practice Test

During the first few moments of rainfall, roads commonly become oilier due to the accumulation of oils and debris that have built up on the pavement. When rain initially falls, it can create a slick surface as the water mixes with these substances. The oils do not wash away immediately; instead, they are loosened by the first droplets, causing an increased chance of losing traction. This can present significant hazards for drivers as the road conditions become more slippery. This phenomenon emphasizes the importance of exercising caution during the early stages of rain, as the risk of skidding or losing control is heightened.