Red ball of light exploding into many small white lights with one strobing along highway.We had left Rapid City that night, and when we got to Wall South Dakota, a bad storm had hit the area. We were just coming out of storm when we had just passed thru Midland. I was driving and the rest of my family was sleeping, when a orange ball of light had come down from the sky and , just before hitting the ground, it blew up. Many small white lights seem to leave in every direction. I woke my wife and told her I had just seen my first fireball lightning. I then noticed a very bright flashing strobe light on side of hill. I showed my wife. It just happened that the highway turned to where it was on the side of the hill. When I got to the top of the hill,it was about 100ft off highway. I pulled up next to it and told my wife I was going to walk over to it. She said no but I said I wanted to know what it was. I got out of my van and walked accross highway,into ditch where it was flashing. I tried to look at it but each time it flashed it blinded me. Halfway there I noticed another to my right. I called back to my wife, who was standing next to our van, look there are two of them. She yelled back "no, thats the same one, it just moved". I then thought to myself that anything that can move that fast is probally nothing to mess with. My wife was yelling lets get out of here so I went back to van and told my wife to wake up my oldest son. I got in and preceeded down highway, when I noticed it was still beside our van. My wife says speed up and out run it.I was going over 100 and it still was still beside us. About 5 minutes later it seemed to fall back about a mile. I said I think we lost it, just then there it was beside us again. Down the road a ways the highway turns towards Pierre, we made the turn and noticed that the light didn't follow us in that direction. About 10 miles down that highway we stopped to check our kids. Everything seemed to be OK. Maybe we just imagined this, my wife said. I looked down the highway back in the direction that we came and saw the light in the distance.! No we d idn't imagine this, I said as I pointed back at it. We both got back in the van and left quickly. We couldn't get a look at it because it was to bright to look at, it lit up the surrounding area, as if it was day. We had a long nervous ride back to Jamestown that night.