The Invisible Danger: "FOG"

16/12/2025

Invisible Danger: Vital Tips for Safe Driving in Foggy Weather

One of the most challenging weather conditions we can encounter during a journey is undoubtedly fog. In rain or snow, you can feel the loss of tire traction, but in fog, you lose your most important sense: sight. Statistics show that fog-related accidents usually occur at higher speeds and have more severe consequences.

What Is Fog?

Fog is a condition where tiny water droplets suspended in the air reduce horizontal visibility at ground level to below 1 km. According to the Met Office, visibility above 1,000 m is called "mist," while below 1,000 m is called "fog." Additionally, the Met Office indicates that "dense fog" occurs when visibility drops below 100 m.

When and Where Is It Seen Most?

Fog is not "uniform"; its location and timing vary according to how it forms:

Radiation/Ground Fog (Night–Morning): Generally forms under clear skies, calm winds, and humid air conditions as the ground cools at night. It is frequently seen in autumn–winter and during pre-sunrise/early morning hours.
Valley Fog: Cold and dense air accumulates in valleys/hollows, causing visibility to drop rapidly.
Sea/Coastal Fog: Forms when warm, moist air passes over a colder surface (sea/cold land) and cools down; common in coastal areas.
Water Edges and Moisture Sources: Areas around lakes, rivers, and dams can increase the risk of fog.
Industrial/Urban Surroundings: It is noted that very dense fog can become even thicker in regions with more particulate matter in some cases.

What Is the Impact of Fog on Safe Driving?

Visibility and Perception Are Impaired: It becomes difficult to perceive speed, distance, and road lines; the risk of "realizing danger too late" increases.
Light Reflection (Glare) Increases: High beams can reflect off fog droplets, creating a "wall" effect; this worsens visibility further. (National Weather Service)
Risk of Pile-ups Increases: If following distance is insufficient, sudden stops become much more dangerous.
Windshield Fogging/Wetness: Condensation makes the use of wipers, defrosters, and air conditioning critical.

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What Should We Do During Fog?

The first rule when entering a foggy road: See and Be Seen.

Reduce Your Speed: Increase your following distance to at least twice (if possible, 3-4 times) the normal. Drive at a speed where you can "stop within the distance you can see."
Use Your Headlights Correctly: Definitely turn on your low-beam headlights. If visibility has dropped significantly, turn on your front and rear fog lights.
Wipers and Defoggers: Operate your wipers to clear moisture accumulating on the windshield and direct the air conditioning/heater to the windshield to prevent fogging.
Auditory Focus: Turn off the radio. If necessary, crack the window slightly to try to hear other vehicles.
Follow Road Lines: Do not use moving objects (like the vehicle driving in front) as a reference while driving in fog. Follow the road lines.

What Should We Not Do During Fog?

Do not use high beams: This distorts vision via back-glare within the fog.
Do not use hazard lights as a "continuous driving mode": Hazard lights are essentially for warning/danger/obstacle situations; emphasizes that they should only be used for short durations while moving under specific conditions to warn those behind of a danger.
Do not stop in the lane/traffic flow: This increases the risk of being hit from behind.
Do not "tailgate" the vehicle in front: Using the vehicle in front as a "guide" is dangerous.
Avoid sudden maneuvers and unnecessary overtaking: Fog distorts distance perception.

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