This morning, at 9:45AM on Thursday, May 14, 2015, I was driving on I270 from Hyattstown, MD toward Germantown, MD, when I saw at about 20 degrees above my horizon, and ahead of me in the sky, 3 objects.They were flying in a straight line, left to right across my direction of travel, and consisted of two silver cylindrical objects that I would guess were about the size of railroad tank cars but taller and maybe longer, and were ahead of a third object that was black, and square or rectangular in shape, and as large as the cylinders.I saw no windows on any of the objects, nor any means of propulsion - no wings or propellers - and no discernible tail features. There was no sign of any smoke or other exhaust features. I was in heavy morning rush hour traffic, in the center lane, and could not pull over to either side to stop for a better view.They were moving relatively slowly, and stayed in view for about 40 seconds before I drove past the point where they were off my right side and out of my sight. If they stayed on that course, they would have passed over the Germantown area.I don't know for sure what they were, and, unless we have technology that I am not aware of, I seriously doubt that they were made by man - homo sapiens.All of my life, I have believed that we are not alone. Now, unless this can be explained away, I am very sure we are NOT alone!