Temporary traffic-control sign
Construction machinery ahead
Thai road sign ตก.4 — Construction machinery ahead. Meaning: Construction machinery is working ahead on or close to the carriageway. 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: ป้ายเตือนเครื่องจักรกำลังทำงาน
Independent English reference · Source: Department of Highways · Sign ตก.4
Road response
On the road
Driver action
What should you do?
Construction machinery is working ahead on or close to the carriageway. Reduce speed before the signed condition and keep enough space to respond safely.
Exam-style scenario
Read the situation
An excavator may swing or move close to traffic inside the work zone ahead.
Best response: Reduce speed and be prepared to stop if the excavator moves or swings toward the live lane.
Sign comparison
Don’t confuse it
This sign
Construction machinery ahead
Compare with
Workers ahead
Key difference
The plant pictogram warns of moving construction machinery; Workers ahead depicts people working near traffic.
Put sign knowledge into practice.
Answer exam-style questions about road signs, traffic lights, and lane markings in clear English.
