Temporary traffic-control sign
Three lanes shift left, then right
Thai road sign ตก.17 — Three lanes shift left, then right. Meaning: Three 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.17
Road response
On the road
Driver action
What should you do?
Three 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
All three lanes move left before returning right beyond an extended work site.
Best response: Hold the current lane through both shifts as all three lanes move left and then back right.
Sign comparison
Don’t confuse it
This sign
Three lanes shift left, then right
Compare with
Two lanes shift left, then right
Key difference
Count the three parallel lane lines moving through the offset; the similar companion diagram contains only two.
Put sign knowledge into practice.
Answer exam-style questions about road signs, traffic lights, and lane markings in clear English.
