Have you ever seen this traffic sign? You can see this only in New York City!
As you know, right turns on red are permitted in many regions of United States. That's why everybody, of course, turns on red without a sign board. But New York City is different.
I've seen many drivers who used to drive out of NYC break this rule. They are not familiar with "on-turn-on-red-everywhere" restriction and may turn on red inadvertently.
If you are new driver in NYC, please remind yourself firmly that you're driving in the City and always stop on red light!
And this is the sign which you never find in New York City (^_-)