It was leaving a thick trail of smoke, steam or exhaust and was illuminated with white and red lights and making no noise.Note: Please post this submission instead of the one I just submitted moments ago. For anyone who might live in Lehi and know where I was talking about, I made a right hand turn after crossing the tracks, not a left. Here is my description again...As I was traveling west on a county road in SW Lehi, Utah, I had just crossed over some railroad tracks and turned right when I noticed this rather large, illuminated object that seemed to be hovering just over the rooftops and it was covered with lights with no true shape to it. If I had to guestimate how many lights there were, I would say approximately 15-20. And mixed in with the white lights were about 2-3 red ones, which were around the perimeter of the craft. I was about 1/4 mile away from it and I would say it was traveling at a rate of about 25-30 mph because I pursued it, but it was staying the same distance from my car. As it moved through the air, it left a rather thick, white trail which looked like either smoke, exhaust or steam. It also seemed to rotate as it moved and the lights kept changing in brightness and position. It made no noise either. As a matter of fact, there were many other cars in pursuit of this thing as it made its way west. Some cars had stopped where people had gotten out to watch it, while others stayed in their cars and pursued it (like me) for about 1-2 miles. However, after about 10 minutes, it dipped behind a large home and suddenly just vanished without a trace. It was truly one of the most amazing things I had ever witnessed. I had no explanation for what I saw. It was my second UFO experience actually because I had seen this same aircraft before a few weeks earlier, only it was a very brief sighting (maybe 10-20 seconds). I should have called the local police to report an unidentified flying object, but didn't. I was also amazed when no one else reported it, considering the number of people on the backroad who either got out of their cars to gaze at this thing or follow it. Both times, I saw this thing coming home from work around 7:00 PM, and so it was dusk and rather difficult to make out its shape since it was getting dark.