pylon
Refers to a tall structure used to support power lines, bridges, or as a marker. In Japanese, often used for traffic cones as well (see sense 2).
Orange pylons were placed at the road construction site.
Specifically a traffic cone; often used interchangeably with カラーコーン. The cross-reference highlights this common usage.
See also: カラーコーン
We put up traffic cones at the parking lot entrance to block it off.