When must drivers stop at an automated railway level crossing with barriers and red flashing lights?

Stop safely when the amber light shows, or when red lights start to flash.
When there are no lights visible.
When the red and amber lights stop flashing.
When the barrier is fully up.

Explantion: You must stop safely when the amber light shows. Flashing red lights have the same meaning as a steady red traffic light - stop safely when they show.

Theory Tester

When must drivers stop at an automated railway level crossing with barriers and red flashing lights?

Control of Vehicle