While driving from Arizona to Eagle Colorado for the holidays I had turned onto I-70 and somewhere (We wrote down the mile marker but cannot find it at the moment) between the Utah border and Fruita my wife and I were talking. The radio was low and our little girl and dog were sound asleep in the back. It was a clear, cold Colorado winter night. Suddenly from the north this huge green-yellow phosphorescent triangular shaped ball of light came across the sky right in front of us! It was so bright and it had a rooster-tail like plume coming off the top of it. In the center of it the light was so bright it almost hurt to look at it. At first I thought it was a meteor but then it slowed down and then speeded up again going north to south. My wife could not stop saying "what is that?! What is that?!" it was pretty frightning. Suddenly these red lights shot out the back of it while it seemed to hover and then it quickly changed direction and rocketed off to the east (Same direction we were traveling) moving so fast that it became a pinpoit of light in a matter of seconds!! We looked for it to come back all the way to Eagle. I have witnessed a few other UFO's in my lifetime but I am SO GLAD my skeptical wife was able to witness this with me. She is still in disbelief.