Minimum speed (30 km/h)
Drivers must not travel below 30 km/h where this minimum-speed control applies, unless traffic or safety conditions require otherwise.
Verified as Thai road sign บ.54-30 from Thai Department of Land Transport sign series on 2026-05-15.
Study guide
Connect this sign to practice
On the Thai theory exam, mandatory signs like Minimum speed (30 km/h) get paired with multi-step scenarios: sequence of turns, lane assignments, intersection priority. Reviewing it next to similar signs in the flow makes those scenarios feel familiar instead of fresh.
Now see it in questions.
Spotting Minimum speed (30 km/h) 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.
