I was driving northbound on U.S. 31, just south of Berrien Springs, at about 4 p.m. To my left (west), I observed a very bright light about 40 feet above an open field. It was absolutely still (not even really "hovering"). It was about 50 to 60 feet west of me. I initially thought it was a private aircraft on approach to a small airport that lay nearby in Berrien Springs. However, as I kept glancing at the light while driving, I realized it was not moving. Then I thought I might be looking at the sun, only to see that the sun was further southwest of me & the light. I kept glancing at it, and wondering what it was. It made no sound, no move. It was not connected to a light pole or any other mechanical apparatus. Then, I glanced again and realized the light had vanished. Nothing remained in the air. The entire event lasted about 3 minutes. I still don't know what I saw. The field was empty and there were no trees, or anything else it could have been connected to.