As I got over the bridge, the lights that I was flashing at to lower their high beam lights, moved off to my right and hovered over a barn that was about 300 feet away. As I got over the bridge I realized it wasn't a car moving to the right. It was about 50 foot off the ground above the barn with a ton of lights around it's oval shape, with some acting like headlites on a car. Underneath there was green and yellow lights rolling much like a barber post goes around but going in a circle. As I got across the bridge I stopped on the side and got out to look at what ever it was. It hovered there for about five seconds and then in a blink it moved to the northwest part of Sioux Falls about 5 miles away. I had my girlfriend and another female friend of her along when we saw this. It happened so fast that no one really got afraid of what we had just saw. The next day in school talking with a friend of mine whose father was in the police department then about what I saw, he mentioned that the whole police department was chasing around the city trying to figure out what everyone was seeing.