Section 24-221(a)

Although it's far from top secret or classified, I'm sure most people are unaware of a law in NYC that carries a $350.00 fine and bans horn honking except in cases of "imminent danger", which is defined as "an immediate threat of harm". With that we can probably rule that if a car is headed towards you on a one way street it may be an appropriate time to make use of your claxon. However, in a situation where the traffic had ground to a screeching halt because its rush hour and your type A personality is on the verge of a heart attack, well that does not constitute an emergency except in your own mind.