i was driving north from las vegas nv., saturday night, feb 25th 2017 aprox time 9 pm. there were many cars on i-15, in both directions. i was headed toward valley of fire about 3 to 5 miles ahead. the sky was very dark, unable to see any stars, when i witnessed three lights ahead, hovering above i-15. there was one red blinking light on the top, one white solid light approximate 40 feet below it, and the seemed to be another white light from right to left crossing the path around the other lights. ive lived in the las vegas area many years and have seen about everything, i figured it was a helicopter or some kind of electric or construction area. i could see nothing approaching the overhead light, just pitch black sky. then nearly underneath the light i leaned forward on my steering wheel, and looked up, just as the red light flashed from above, i saw the complete silhouette of a very large flying saucer. i was shocked, this was the last thing i was expecting to see. the red flash slowly dissipated over the round edge of the disc as i passed under it. i don't think anyone else on the i-15 passing under it realized what it was. i pulled into the valley of fire exit a few minutes later and looked back, nothing in the sky but stars and a few clouds with a clear view. i don't know why the sky was so black at the sighting.