mandatory sign
Straight or left only
Thai road sign บ.46 — Straight or left only. Meaning: Drivers must continue straight or turn left at the junction ahead and must not turn right. 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: ป้ายให้ตรงไปหรือเลี้ยวซ้าย
Independent English reference · Source: Department of Highways · Sign บ.46
Road response
On the road
Driver action
What should you do?
Drivers must continue straight or turn left at the junction ahead and must not turn right.
Exam-style scenario
Read the situation
Your lane sign permits ahead or left while your passenger asks for the road on the right.
Best response: Continue ahead or take the left branch, but do not use this lane for the requested right turn.
Sign comparison
Don’t confuse it
This sign
Straight or left only
Compare with
Straight or right only
Key difference
The branching arrows allow ahead or left but not right; the mirrored companion permits ahead or right.
Put sign knowledge into practice.
Answer exam-style questions about road signs, traffic lights, and lane markings in clear English.
