silent cop

noun

1. informal.
   a small hemispherical traffic marker at an intersection

Example Sentences

Moss wanted to say so many things—to tell his mother that he loved her, to express his admiration for Kaisha and Reg, or even to beg the silent cop who sat in the back with them to loosen the zip ties at his wrists—but he knew not to.

From Literature

The nature and breadth of Ford’s inquiry about silent cop cars, including where the idea originated from, is unclear because the company requested that the full text be redacted because it contains “confidential and proprietary” information, according to a Ford spokesperson.

From The Verge

Be that as it may, he soon proceeded to unload these, as well as the interesting junk which he had gathered, the most surprising object of which was the dilapidated revolving traffic sign lately discarded by the Bridgeboro police department in favor of a lighthouse or silent cop, so called.

From Project Gutenberg