A policeman who controls the flow of automobile traffic(noun)
WordNet. Princeton University. 2010.
Use "traffic cop" in a sentence
"I looked out over Madison Square, that wonderful, joyous, wintertime square; looked out over the far-off helmet of the mustached, white-gloved, giant traffic cop toward a still-nonexisting Flatiron Building; looked down onto that narrow Fifth Avenue and strange, strange Broadway, and suddenly I had to close my eyes because actual tears were smarting at the very nearly uncontainable thrill of being here."
"I shoved Paul into the hall, and like a traffic cop I pointed to the French doors leading to the terrace, on which were arrayed a wooden partition wall with ivy-covered trellises as well as an antique statue of the Buddha that Paul had brought from Tibet and a small reflecting pool."