According to New York State Law cyclists should signal on the road. [depicted left] Most hand signals are made with the left hand. The reasoning behind this is that bikers are on the right side of the road. As we know here in New York City, this is not always the case (some bike lanes actually run on the left side of the road like on 6th avenue). My advice is to point with whichever hand is most visible to traffic.
There’s a few rules specific to New York City. First, all riders must have both front and rear signal lights at night. [Depicted right] I’ve found this to be a great practice since my black bike blends in with the night darkness. It’s simple and makes you visible. I personally like the ones that flash because they attract people’s attention more than fixed lighting. The other requirement is for bikers to have a signal bell (or other honking device). Before I moved to New York I did not have one, but the benefits were easy to see (and hear). A bike bell is very distinctive and lets people know a bike is coming whether they see it or not.