prohibition sign
Speed limit (30 km/h)
Thai road sign บ.32-30 — Speed limit (30 km/h). Meaning: Drivers must not exceed 30 km/h from this sign until the restriction ends. Catalog status: additional official road-sign reference.
Thai name: ป้ายจำกัดความเร็ว
Independent English reference · Source: Department of Highways · Sign บ.32-30
Road response
On the road
Driver action
What should you do?
Reduce speed to 30 km/h or less before entering the controlled section.
Exam-style scenario
Read the situation
A 30 km/h sign appears before a built-up section while your vehicle is moving at 45 km/h.
Best response: Slow from 45 km/h so the vehicle is at or below 30 km/h in the built-up section.
Sign comparison
Don’t confuse it
This sign
Speed limit (30 km/h)
Compare with
Minimum speed (30 km/h)
Key difference
A red-ring 30 is a maximum that must not be exceeded; the blue 30 is a minimum when conditions allow.
Put sign knowledge into practice.
Answer exam-style questions about road signs, traffic lights, and lane markings in clear English.
