Temporary traffic-control sign
Two lanes shift left, then right
Thai road sign ตก.15 — Two lanes shift left, then right. Meaning: Two traffic lanes shift left and then return to the right through the work zone. 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: ป้ายเตือนเบี่ยงเบนการจราจร
Independent English reference · Source: Department of Highways · Sign ตก.15
Road response
On the road
Driver action
What should you do?
Two traffic lanes shift left and then return to the right through the work zone. Reduce speed before the signed condition and keep enough space to respond safely.
Exam-style scenario
Read the situation
Two lanes shift left and later back right, requiring both streams to follow the temporary markings.
Best response: Remain within the chosen lane while both live lanes move left and later return right.
Sign comparison
Don’t confuse it
This sign
Two lanes shift left, then right
Compare with
Traffic shifts left, then right
Key difference
Two parallel lanes shift left and back right; the single-line version applies to one lane only.
Put sign knowledge into practice.
Answer exam-style questions about road signs, traffic lights, and lane markings in clear English.
