North Carolina driving lesson · Defensive Driving & Hazards
Rain, hydroplaning, flooding, fog, snow & ice
A 4-minute lesson from the North Carolina course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.
Wet or frozen pavement multiplies your stopping distance. The first minutes of rain are the slickest, flood water is deadlier than it looks, and on ice you should slow to a crawl.
Know the rule
In rain you must use headlights and wipers. NC requires headlights whenever wipers are on due to bad weather.
A thin sheet of water gets between the road and your tires so they lose contact. It can start as low as 30 mph in water little more than 1/8 inch deep.
Never use cruise control when it's raining or has been raining. Worn or underinflated tires raise hydroplaning risk; for skids, keep pressure on the high side of the maker's range.
Never drive through standing water: it may be deeper than it looks and the road may be washed out. Inland flooding caused 85 percent of tropical-weather deaths in NC since 1970, half from driving into known flooded roads.
Watch for shady spots, bridges and overpasses, which freeze first. In a snowstorm, slow down, use wipers and low beams. Reduce speed by more than half on packed snow and slow to a crawl on ice.
It starts raining after a dry week. For the next 10 to 15 minutes, oil and dust make the road extra slick. Drop 5 to 10 mph below your dry speed, double your following distance, and turn cruise control off.
Check your understanding
Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.
Compared to dry pavement, how much farther can stopping distances be on wet pavement?
Two to ten times farther
About the same distance
Only slightly farther, under 10%
Up to 50 times farther
Answer: Two to ten times farther
Stopping distances on slippery pavement increase from two to ten times farther than on dry pavement.