Low circular light/flying object and multi-directional changing lights in the sky

This is something that I experienced back when I believe I was 16/17. I was driving my girlfriend home one night, on Humboldt Rd. just passed over the highway heading away from the city. As we were driving up to the left I saw this circular light. The best way I can describe it would be that of light coming out of a lampshade that angles downward. This object was not very high, had absolutely no other lights such as a tail light on helicopters or any wing lights, and made absolutely no sound, or no sound we were aware of. The object travelled exactly the same speed as traffic. As soon as I saw it and realized it wasn't a glare or reflection I asked my girlfriend what the hell that was. She looked and watched it in awe. As we drove down the road watching it, it suddenly literally just took off. Instantly flew forward out of view, I've never seen anything move so fast in my life. It was very eerie, I felt excited because I knew I saw something that is very rare to see and something some people simply can't believe exists as they haven't experienced it themselves. I dropped her off and she too was shocked and knew she saw a "UFO". I haven't seen anything of that nature since. However, in summer of '99 I was swimming in the backyard of a friends house around 3-4 a.m. when we saw a blinking light as far as the stars. Now, this blinking light we found very odd, especially the individual whose pool it was because he watches the stars a lot, because this light changed direction numerous amounts of times. We would watch this light blink once in one area of the sky. About a minute later it traveled I would say the length of the big dipper and blinked again. Then another minute later it would blink up in a total different area as it had changed course. We watched this object for approximately 20-30 minutes. Very odd.
Date, time, and duration of sighting all appear to be approximate.  PD