Ch. 6 · Hazardous Areas

In dense fog during the daytime when visibility is less than 100 meters, you must turn on your headlights, clearance lights, tail lights, and other lights while driving.

[True / False · Medium]

Hikari

Dense fog under 100 meters sounds dangerous, so turning on lights makes sense—I'd say true?

Misaki

Actually, it's false. The trick is the number: the rule says you must turn on lights when you can't see 50 meters ahead, not 100.

Hikari

Wait, so at 100 meters visibility I don't need lights yet?

Misaki

Correct. Remember 50 meters for regular roads—100 is still above the threshold, so this statement is wrong.

Source: Ch. 6 Hazardous Areas · Section (第3節 夜間 - 灯火) · Rules of the Road, Ch.6 §3 (Night) / 2 Lights (1) — Even in daytime, turn on your headlights, side lights, and tail lights when you cannot see 50 m ahead (200 m on expressways), e.g. in tunnels or thick fog.

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Source content excerpted from the NPA “Rules of the Road” instructional manual, in the public domain under Japanese Copyright Act Article 13(2). Explanations are AI-assisted and copyrighted by the MenkyoQuest editorial team.