Yep your right, good deductive reasoning. I checked with AI.
This is a European traffic warning sign that signifies Fog or Sudden Reduced Visibility ahead.
The red triangle indicates a general warning to drivers to be alert, while the pictogram inside shows the rear half of a car entering a thick wall of horizontal lines, which represent dense fog, smoke, or heavy mist.
When you see this sign, it means you should expect driving conditions to change quickly. The rules of the road for this sign generally dictate that you should:
Reduce your speed to match your visible stopping distance.
Increase the distance between your vehicle and the car in front of you.
Turn on your fog lights (or dipped headlights), but avoid using high beams, as they will reflect off the fog and blind you further.