I-9 Tonnelle Avenue area quite popular for them, as there are several cheap, hourly motels/hotels located in this area. Also, many tourists stay there believe it or not, who visit NYC, but can't afford NYC hotels since it is relatively easy to get from here to NYC. That's also explain why police cars circling around Tonnelle Avenue area. There are a lot of stores, car auto repair shops truck stops, etc. as well. That's, as seems, this area always busy day or night. so I would not call this area very unsafe, but would not recommend you to take a walk middle of the night neither.
By the way, one good thing about this hotel, you do not need to go thru lobby, you can walk around the hotel and walk up the room without people in the lobby even see you, of course, always watch out any police cars or suspicious activities around the hotel. Because It is cheap hotel, does not mean you will be get busted, consider it that a few months ago cops busted a luxury hotel in secaucus meadowlands area. I did say in other thread that "when you do go incalls, there's always a risk involves!"
be safe..