Danger of falling rocks ahead
This sign warns that rocks may fall onto the road ahead. Reduce speed and be prepared to stop or avoid debris. Foreign drivers should note that such hazards can appear suddenly on mountain roads.
Verified as Thai road sign ต.40 from Thai Department of Land Transport sign series on 2026-05-15.
Study guide
Connect this sign to practice
Warning signs like Danger of falling rocks ahead test whether you spot the hazard early enough to react. The Thai theory exam often pairs them with stopping-distance, visibility, and right-of-way questions, so practising the symbol alongside its scenarios makes the wording less of a trap.
Now see it in questions.
Spotting Danger of falling rocks ahead in isolation is one thing. Recognising it inside a real exam-style question, among lookalikes and trick wording, is another. The diagnostic mixes it in for you.
