I was traveling south on 35w between elko and northfield exit.I just happened to look to the east when I saw a light that seemed to follow me that whole way getting brighter and lighter while following me down the freeway going the same speed as me about 70MPH . At one point I looked at it and it seemed to shoot a good distance to the south in what was maybe a 1/2 second. I have not seen anything like this in my lifetime. I have always been intrigued by the thought of seeing something like this but when it happened I was filled with more fright than anything else. When I stopped at exit 69 the object stopped as well. When I turned to the east on HWY 19 the object moved out of the horizon to the north which is towards the metro and the airport. It just seemed very strange that this thing was moving parallel to me for so long then just left out of view. The strangest part of the whole experience is when the object seemed to have a burst of power or something cause the light seemed to get a lot brighter for about 5-10sec then fade to its normal brightness.