3 lights at each corner of triangle

I was driving from Claymont to Middletown, as soon as I passed exit 9 I noticed 3 lights hovering off the right as I going south down I-95. I noticed that they were not planes lights or building lights or even tower lights. When I got closer to it I noticed it was hovering over Wilmington near the cinema. At that time I saw it shift and change position. There were many cars on the road and most of us were driving over the limit until the lights of the triangle moved around. Then we slowed down in amazement before we drove past it. It was strange how the lights shifted and even though the triangle was black as night you could see the outline of it.