I was driving home at night on i-80 in vallejo and i couldn't help but notice a huge aircraft flying slowly to the right of the freeway. it seemed to be coming towards the freeway. the blinking lights caught my attention at first and i noticed how large it was and that it was flying very low and very slow. at first i thought it was an airplane in trouble and that it was going to try to land (?) on the freeway. but as i watched i noticed that it was much, much larger than an airplane and although i couldn't make out its shape, i could see an outline. it had blinking lights that seemed to be coming towards the freeway. to my knowledge an airplane cannot travel at such a slow speed and that low to the ground without crashing. there was a lot of traffic on the freeway and i could tell others were watching this (?) as well. drivers were slamming on their breaks to watch. it was almost a panic situation and i thought there was going to be an accident so i decided to get off the freeway. but before i could safely pull over it changed direction and was moving away from me. now it was traveling east towards the hills. i kept watching it as much as i could, as was everyone on the freeway. its lights were blinking randomly in no particular order and one side of the aircraft (ufo) was tipped towards the ground. i could see the outline but i couldn't make out the shape. it was just huge and intimidating. it looked as if it was searching for something or trying to land. moving slowly, all of a sudden the lights blinked off and whatever it was just disappeared. as in vanished! i did see the lights go out and thought it was strange that something that large would/could just shut down in mid air. so, i pulled off the freeway and tried to locate something to indicate that whatever it was, had moved on or landed; but nothing was visible. i found nothing, no lights, no trace that it had been there. i was somehow glad i didn't see a large ufo on the ground. i have no idea what i would do if it was there. i was confused and a little afraid so i drove home. it seems like it was not trying to hide. nothing that big could hide. however, if we do have visitors i would like to know for sure what they are and what they are planning to do. i felt uncomfortable after this experience. i do hope others will find the time to report what they saw and what they think of this situation. we are not alone!