Noun
traffic cone (plural traffic cones)
A cone-shaped marker, generally made out of plastic or rubber, that is placed on roads or footpaths to temporarily redirect traffic in a safe manner.
Coordinate term: construction barrel
If you have a statue in the city centre you could go past it every day on your way to school and never even notice it, right. But as soon as someone puts a traffic cone on its head, you've made your own sculpture. Banksy