Green light flash in the sky approx 100 yards from intersection on a diamond-esque, dark colored shape low in the sky, vanished

I was driving to work and noticed a green light flash in the sky as I came up a hill before Lake rd turn, it flashed twice and appeared to be on the "nose" of a large diamond-esque shaped dark craft that was very low in the sky, much lower than a small plane would fly, it was maybe 10-15 seconds and it just vanished. It didn't propel forward, up, or down, just vanished. There was an 18-wheel truck headed north at the same time that braked heavily at the same time I did but then proceeded on. I slowly turned onto Lake Rd but didn't notice anything else.