What can I call a person who directs traffic?

I'm referring to people in bright orange or green vests who direct automobiles. I thought of road workers, but it's not specifically around road work. Is there a word for "traffic-directors"?

Such a person may be called a traffic director, traffic controller or traffic conductor.

They're called traffic cops in the US. (Or, more formally, traffic police.)

If they're police officers, than as Gnawme says the common term is "traffic cop".

Construction workers who are working on a road or something near a road so that they are interfering with traffic will normally have one of their members direct traffic. This person used to be called a "flagman". In these politically-correct days, he or she is now called a "flagger". (While I don't have statistics on this, from my anecdotal observation, these days if the construction crew is more than 2 or 3 people the flagger is almost always a woman.)

It looks like the (US) industry term is flagger, that is, if it's not specifically a traffic cop.