Legal Question in Civil Litigation in New York

If you know the vicariously-liable person, you should name them at the start. You can always add them to the suit later as long as the statute of limitations has not run out. Even if it has run out, if the person you sued and the vicariously-liable person are "united in interest" you MAY be able to have the claim against the extra defendant sustained even though the Statute has expired, but don't count on it. If you know that SOMEONE is vicariously liable but you don't know who, name a "John Doe" defendant, describing John Doe as the viicariously-liable party, and then move to amend when you know who it is. That motion goes through much more easily than a full-bore motion to add a party.