Why Fog Is So Dangerous

Fog doesn’t just blur the landscape; it distorts distance, dulls headlights, and makes even familiar roads feel strange. Visibility can drop from miles to metres in seconds, and that’s when most fog-related collisions happen. Drivers misjudge gaps, follow too closely, or simply don’t realise how little they can see until it’s too late.

The rule of thumb? If you can’t see more than the length of a football pitch (around 100 metres), it’s time to slow down, turn on your fog lights, and rethink your driving approach.

1. Slow Down; and Stay Smooth

Speed is your biggest enemy in fog. The denser it gets, the less time you have to react. Ease off the accelerator and drive gently, using low gears where appropriate. Avoid sudden braking or sharp steering; smooth inputs keep you in control and make it easier for drivers behind to anticipate your moves.

And remember: it’s not about holding up traffic; it’s about staying alive. Better to arrive late than not at all.

2. Use Lights Correctly

Turn on dipped headlights, not full beam. High beams reflect off the fog, creating a white wall that makes visibility even worse. Rear fog lights should only be used when visibility drops below 100 metres. As soon as conditions improve, switch them off; they’re dazzling to anyone behind you.

If your car has automatic lights, check they’re actually on; some systems don’t detect fog properly. In older cars, switch them manually to be sure.

3. Keep a Safe Distance

In fog, the two-second rule becomes the four-second rule. Double your usual gap to the car ahead so you have time to stop safely if they brake suddenly. Don’t be tempted to follow their taillights too closely as a guide; if they make a mistake, you’ll make it too.

Instead, focus on the road edge markings or kerb as a reference point, and keep your attention soft but steady; scanning, not staring.

4. Use Your Ears as Well as Your Eyes

Fog muffles sound, but it’s still a valuable tool. Open your window slightly when approaching junctions or crossings to listen for oncoming traffic you can’t yet see. It’s especially useful in rural areas where headlights may appear suddenly out of nowhere.

5. Don’t Rely on Technology Alone

Modern driver aids like lane assist and adaptive cruise control can struggle in fog because cameras and sensors are partially blinded. Keep control manually. Sat navs are helpful, but they can’t tell you what’s around the next bend. If conditions get truly severe, pull over somewhere safe; ideally a car park or service area; and wait it out with your hazard lights on only if necessary.

6. Watch Out for Hidden Hazards

Fog often comes with damp roads and cold temperatures. That means slippery surfaces, especially on bridges and shaded stretches. Keep your steering gentle, avoid harsh acceleration, and stay alert for pedestrians or cyclists without lights. Many wear dark clothing and can appear just feet ahead of you.

7. Keep Windows and Mirrors Clear

Condensation inside the car can be as bad as fog outside. Use your demisters and air conditioning to keep windows dry. Wipe mirrors regularly, and don’t forget your rear window heater; a foggy mirror is as dangerous as a foggy windscreen.

8. Know When to Stop

If visibility drops to near zero, don’t try to “creep along” hoping it’ll clear. Find a safe place to stop completely; never on the hard shoulder unless it’s an emergency. Use your parking lights or sidelights if you’re stationary in a lay-by or car park, and wait until you can see again before setting off.

Useful UK Resources

• UK Highway Code – Rules for Driving in Fog
• AA – Driving in Fog
• RAC – Fog Safety Advice