My wife, mother, and I were driving on Interstate 5 heading northbound through Fife, WA. The time was approximately 2:45pm on 01/31/2013. I looked up into the cloudy sky from my car's windshield, just looking around for no reason. I noticed 4 balls of white light, and first thought they were just birds due to their flight pattern. But then I took a 2nd look and realized the 4 balls were shiny and reflective like a piece of metal, and then took notice to the way they were moving. They flew forward, then quickly slowed to a stop and headed the opposite direction. They were also moving in a semi-circle, "S" like pattern. Then they would disappear for a second or two and then reappear. I told my wife and mother to look at the 4 balls/objects, and they noticed the shiny, reflective appearance also. We all three ruled out the possibility of these being birds or known aircraft due to the impossible flight pattern of the objects. After about a minute more of driving the 4 balls were no longer in sight, but may have stil been there. We felt really strange after this and continued to think about it and discussed it further over dinner. A friend of mine told me I should report this to a website that he knew of, (MUFON).