Core idea
Fog reduces the distance at which hazards become visible.
Why it matters: safe driving depends on recognizing a situation early, leaving enough time to decide and avoiding actions that surprise other road users. Read the corresponding section of your official state driver handbook for any local rules and exceptions.
How to use this knowledge
Slow to a speed that lets you stop within what you can see and use appropriate lighting.
As you study, picture a real intersection, road or parking area. Ask yourself what you can see, what might be hidden, who else could be affected, and which action creates the most predictable and safe outcome.
A mistake to avoid
Using high beams in dense fog when they reflect glare.
Rather than memorize one answer, identify the hazard and the reason the safer response works. If the situation depends on a law or traffic-control device, confirm the rule in your state's current handbook.
Two-minute review challenge
Describe how your following distance should change in fog.
Say your answer aloud, then check it against an official handbook or trusted driver-education material. Write down anything you could not explain clearly and revisit it tomorrow.
Build your permit study routine
- Read the relevant official handbook section.
- Summarize the main idea in your own words.
- Practice with new questions, not just repeated answers.
- Review errors and return to this topic later.