Returning from meeting in New Jersey, I was raveling north on 9w along Hudson river passing through town of Marlboro. Coming up the hill near a gas station, I noticed two lights I assumed were helicopters coming from SW moving NE. About the same time, two jets on a steep angle w/afterburners on were flying on a more northerly path. Thought they came out of Stewart Air Force Base. As that was occuring, a large shadowy object appeared directly overhead moving from the west towards the Hudson river. Pulled off the road as much as possible. There was construction at the time that kept me from pulling completely off road. Lowered passenger window and jumped across seat and leaned out window on my back. Looking directly up at the bottom 200, I saw a dimly lit cast shape triangle several hundred feet long. No sound, seemed to move slowly. The nose appeared to be over the Marlboro school before I saw the back. Back was rounded with a thin line of blue lit windows for lack of a better description. The light was similar to a black light in color. It continued on its path then turned south as it passed over the school. I could not understand why the jets and choppers went north or why everyone behind me did not pull off the road. My immediate thought was military in origin as we were near Stewart shook me up quite a bit. Drove home and told girlfriend what happened and swore her to secrecy. The following day she told a co-worker of ours who told her his wife saw the same thing in Hyde park, New York the same night. Hyde park though is north of Marlboro, I saw it travel south. Sighting has stuck with me as more sightings of a giant triangle over the years. Also, I thought if it were military, we would know by now. Always been a believer, but with a skeptics eye. Always hear about strange lights or beams with other sightings, but this ship had no such thing . NOTE: The above image is a rendering.