10/31/12 I was headed northbound on 680 through San Ramon CA between Alcosta and Bollinger exits. At 10:10pm. I had noticed a white, red and blue lights of what I thought was a plane. I had not seen a flight path right over freeway so I wondered if they were going to do an emergency landing. As I got closer I was shocked to realize that I was passing the object and could now see the belly if it. It had five lights in a pentagon formation that lit up the underside. It looked as if it were stopped right above San Ramon Valley Blvd that runs parallel to freeway. It was very low, a little above the tree line. As I was driving I had to keep my eyes on the road but kept glancing at it. I decided to get off at exit exit and flip around. As I neared exit I looked back and could only see 3 white lights now that faded quickly. It was gone before I could turn around. I called my aunt then and told her what I saw. There was light traffic at the time yet at least five cars got off on same exit as I did but they all turned the other way. I remember thinking at the time I saw it if anyone in the other cars had seen it as well.