A large disk craft hovered over 635, then instantly shot off to the south, hovered as a white light on the horizon, then disappeared

I was driving home from work around 9:30 pm, eastbound on 635 (LBJ Freeway). Up ahead of me, I saw the UFO hovering over the highway. It was very large. I am going to guess that the freeway was a total of 6 lanes (both sides) then. The UFO spanned most of the lanes. It was very low to the ground...maybe 50 feet off the ground. It looked to be made of silver metal with opaque windows around the middle of it. The windows encompassed the height of the craft and were divided by vertical metal dividers. (I have attached 2 pictures that are not mine but are very similar to the craft. One of the examples has the vertical metal dividers similar to what I saw, but the dividers were not as wide.) This craft was very close, so it wasn’t vague lights or shapes off in the distance. It was very clear to see, as clear as the other cars on the freeway. As I drove towards it, I wondered if I was the only person who could see it, because everyone just kept driving. No one was pulling off to the side of the road. There were definitely other cars. This was back in the 70’s and at night, so Dallas did not have the congestion it has now, but there were definitely other cars. I remember thinking to myself “Why is everyone driving like there’s nothing strange going on?”. And then thinking, “well I am not pulling over because I do not want to draw attention to myself”. Almost at the point I was going to have to drive under it, the UFO shot off to the south. In an instant, it was a small dot of white light off on the horizon. I don’t know for sure because it has been so long, but I think it was joined by 2 other UFO’s (also small white lights). It/they hovered there on the horizon for a few seconds and then instantly disappeared.
I kept the sighting to myself for years because I thought people would think I was crazy. I did not realize there was a place to report it, but recently stumbled on this website. I wanted to document the sighting because even after approximately 47 years, the memory is still very vivid. It was an extremely close encounter.