Temporary traffic-control sign
Road survey ahead
Thai road sign ตก.1 — Road survey ahead. Meaning: Survey crews are working ahead. 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: ป้ายเตือนสำรวจทาง
Independent English reference · Source: Department of Highways · Sign ตก.1
Road response
On the road
Driver action
What should you do?
The driver should slow down and watch for survey personnel and equipment on or beside the road.
Exam-style scenario
Read the situation
Survey staff and measuring equipment may occupy the roadside beyond this temporary warning.
Best response: Slow before the survey area and leave safe clearance for staff and equipment beside or on the road.
Sign comparison
Don’t confuse it
This sign
Road survey ahead
Compare with
Workers ahead
Key difference
The survey warning concerns measuring staff and equipment; the worker-symbol sign covers road crews carrying out construction work.
Put sign knowledge into practice.
Answer exam-style questions about road signs, traffic lights, and lane markings in clear English.
