Generally, the charge/ticket of obstructing a driveway does not depend on whether the driveway is in use or if it has ever been in use. In Illinois a charge such as this largely depends upon whether or not the allegedly violating vehicle was in fact parked in front of a driveway or not. I do not know if New York has different standards that Illinois does or not. You may be well suited to consult with an attorney licensed in New York who routinely deals with traffic violations.
I am a NY lawyer and the first answer accurately outlined the applicable law. If you park in front of a driveway, you're guilty of the charge. All the rest of those suggested "defenses" sound great, but they don't hold any water whatsoever. It was a driveway and what if the tenant wanted to have that car which had been sitting in the driveway towed away? Etc.? Your so-called "defenses" are nothing more than excuses and they don't cut it.
I respectfully suggest you speak to a local Queens lawyer and expect to hear about the same as is written here. Or save time and send in the fine. It may be cheaper in the long run.
Good luck nonetheless.
This answer is not intended to form an attorney/client relationship and any answers do not constitute direct legal advice and should not be followed unless and until you have spoken with an attorney of your choice.
You have no defense. You admit that you "thought" you could do it because of the nature of the car in the driveway. You were wrong. A drive is a driveway, and there is no way you will convince a judge that the ticket was wrongly issued. Your thought process is irrelevant---it cannot be denied that you obstructed a driveway. Game. Set. Match. Pay the ticket and move on with your life.