I pulled up to the red light at 1825 and 10th (I was on 10th, about to make a right onto 1825 to drive through Pflugerville toward FM 685) at 7:20pm. I know the exact time because I was on my way to pick up my daughter. There was a car already stopped in the right turn lane, a silver Lexus(?) with two adult women in the front. As soon as I stopped, I noticed in the sky ahead of me, around 45-50 degrees above the horizon to the north east, lights in the sky off in the distance. It only took a second or two to see that they were lights scattered around the edge of a triangular shape whose darker silhouette could be made out against the sky. It appeared to be slowly rotating as if almost standing on end and turning it's flat edge toward me. I rolled down my car window and pointed up at it, turned to the two women in the car next to me and asked if they were seeing it. They indicated they had been watching it for a minute or two already. I watched for a few more seconds, then the light changed and I drove forward and took a right onto 1825. I could still see it in between the buildings of the elementary school for a few seconds then it appeared to vanish. I thought I'd have a better view of it once I turned left onto 685 toward Hutto, but there was nothing to be seen.
I'm having a hard time describing the lights around the edge. They were not like regular bright pinpoint airplane lights, they were more whitish orange, and seemed larger. The object itself appeared to be around a mile away, and very large, however it was kind of hard to judge distance so it could have been more. I did have an impression of immense size however, like something moving pretty slowly, that was very big. I wish I'd had the presence of mind to try to take a photo or ask for the two women's contact numbers, but I did not. The lights on the object were one of the reasons I thought it was far away - they looked very large, and indistinct as though off in the distance, plus I could see the darker shape of whatever they were attached to in-between them.
The other reason that I'm pretty sure about what I saw is that I run a lot at night, and can always see planes in a holding pattern or approaching to land near and around where we live, and over toward Taylor, Hutto and parts of Pflugerville. These lights were nothing at all like the plane lights I'm used to seeing - they were lower, moving slower, were larger and completely different in terms of brightness. It was a very bright, clear night.
I've attached a map showing where my car was stopped, and the direction I was facing when I saw it.