Traffic signals ahead

Where you'll see it

On any road before a intersection with traffic light

What it means

To warn that there are isolated and particularly new traffic lights or traffic lights near an isolated traffic light at a pedestrian crossing ahead

What you must do

Slow down immediately and be ready to stop if the light changes from green to amber. Make sure there are no pedestrians or cross-traffic who might not obey the signals

Source: Signs manual W301, TW301