Strange bright cloud moved with car for several miles, then zipped off as silver saucer.

1972, moving from Illinois to California. Going south out of Provo, Utah on a 2 lane highway. Notice a strange, bright cloud up off my right front. Seemed close, maybe 1/8 to 1/4 mile. It seemed to tag along for sevetal miles and I started to take more and more interest. All of a sudden this thing takes off, turning into a perfect silver saucer. I couldn't believe it! When I came to my senses I got my camera out of the glovebox and started shooting in the direction of the craft, still driving. The saucer zipped across the desert and way to the west I could see the late day sun glint off the object as it now hovered over mountains in the distance. When my pictures were developed I only had one photo with a glared fuzzy object in it. I am currently looking for someone with digital enhancement equip. to look at it. Now for the final words. I know what I saw.