Driving in fog drastically reduces visibility and demands adapted speed, the right lights and clear communication. Wrong light choice or too little distance can cause pile‑ups. Follow these points to stay safe.
Correct light use in fog
| Situation | Recommended lights | Why |
|---|---|---|
| Dense fog in open areas | Low beam + rear fog | High beam reflects back and reduces visibility |
| Light fog/city driving | Low beam, fog lights as needed | Good visibility without glare |
| Motorway with traffic | Low beam, rear fog only in very poor visibility | Avoid glare and remember to switch off when visibility improves |
For light types, see Lights and types. For practical use, see Using lights and signals.
Speed, distance and positioning
| Element | Recommendation | Effect |
|---|---|---|
| Speed | Reduce clearly below the limit | Increases reaction time and reduces risk |
| Following distance | At least 3–4 seconds, more in dense fog | Prevents pile‑ups |
| Positioning | Hold a stable line, use the edge line as reference | Reduces drift |
Read more in Speed and distance. For sensor limits, see Cleaning sensors and cameras.
Visibility improvements and maintenance
| Measure | When | Why |
|---|---|---|
| Wipers and washers | When a moisture film builds | Better visibility and less glare |
| Defogging the windscreen | When fog/condensation appears | Clear view |
| Clean front and rear lights | Before and during driving | Better visibility for you and others |
See Wipers and washers and Defogging and visibility.
Communication and interaction
| Action | Practical tip |
|---|---|
| Indicators | Show intention early when changing lanes/exiting |
| Hazard lights | Only for acute danger/stop; park safely |
| Sound signal | Avoid horn; use only for immediate danger |
See also Communication with other road users.
If you must stop or there is an accident
- Switch on hazard lights and reduce speed smoothly
- Stop in a safe place off the lane; place the warning triangle with extra margin
- Call 112 if there is pile‑up risk; in tunnels or demanding conditions use eCall/SOS
- For first aid and safe zones, see First aid and conduct at accidents
Pre‑departure checklist in fog
- Clean windows, mirrors and lights
- Correct light setting for the conditions
- Extra following distance and a route plan