prohibition sign
No changing lanes to the left
Thai road sign บ.10 — No changing lanes to the left. Meaning: Drivers must not change lanes to the left where this sign is posted. Learner-manual coverage: this identity is shown in the current DLT car-driver learner manual. Inclusion does not mean it appears in every theory test.
Thai name: ป้ายห้ามเปลี่ยนช่องเดินรถไปทางซ้าย
Independent English reference · Source: Department of Highways · Sign บ.10
Road response
On the road
Driver action
What should you do?
Drivers must not change lanes to the left where this sign is posted. Stay in the current lane until the restriction ends or another sign allows the lane change.
Exam-style scenario
Read the situation
Your exit is approaching on the left, but this sign applies while you are still in the centre lane.
Best response: Stay in the centre lane through the restriction, even if that means missing the approaching exit.
Sign comparison
Don’t confuse it
This sign
No changing lanes to the left
Compare with
No changing lanes to the right
Key difference
The bent lane-change arrow moves left, prohibiting only that lateral move; the companion sign bars a move to the right.
Put sign knowledge into practice.
Answer exam-style questions about road signs, traffic lights, and lane markings in clear English.
