No agricultural vehicles
Agricultural vehicles are not permitted on this road. Drivers of tractors, combine harvesters, and similar farm machinery must not proceed beyond this sign. This restriction applies until an end-of-restrictions sign is posted.
Verified as Thai road sign บ.22 from Thai Department of Land Transport sign series on 2026-05-15.
Study guide
Connect this sign to practice
No agricultural vehicles is a "don't", and the Thai exam likes to probe the until-when part: where the prohibition lifts, what overrides it, and whether common driver workarounds are still legal. Practising it in context makes the answer obvious.
Now see it in questions.
Spotting No agricultural vehicles 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.
