New Year's Eve 2011 UFO sighting around 8:30 pm south of Flagstaff, ArizonaAround 8:20 to 8:40 pm local time, my girlfriend and I were traveling on Interstate 17 Northbound from Sedona to Flagstaff. About 5 miles south of Stoneman Lake, my girlfriend noticed a glowing sphere moving initially north and then northwest. I was driving and peered under the top right section of the windshield and saw a large yellow sphere moving parallel to the car then moved very quickly in front and finally disappearing in front of the car. This all took about 5 secs. The yellow, slightly greenish sphere was fully illuminated and appeared like a huge falling star or giant fireball. As it passed our car, the glowing appeared more in front of the sphere like only the semi-circle was lit. Then when it was fully in the front windshied, only red lights were visible, which made me think it was a plane, but it disappeared in a cloudless night. If it wasn't for the huge fireball like appearance, I would have thought it was a plane. The relative size of! the vision was about two times the size of a full moon. My girlfriend did see the sphere about 2 or 3 seconds more and said the color was changing from green to yellow, though I only saw a yellowish globe. It traveled mostly parallel to the ground then made about a 30 degree rise as it crossed in front of the car.