What is the meaning of this sign?

1. Flashing orange light warning of an approaching level crossing.
2. Correct answer: Flashing orange light at road works.
3. Constant (not flashing) Orange light when traffic lights are not working.
4. Constant (not flashing) orange light warning of an approaching forked junction.

WhyA flashing orange lamp marks road works. Be ready for narrowing, workers and machinery.