Glowing Orb Seen Over Freeway In California, Aug 1999, UFO Sighting News.

Date of sighting: August 10, 1999 (reported today)
Location of sighting: Rancho Santa Margarita, California
Source: MUFON #82195

The image with this report was made by the eyewitness and I think it really gives us a great idea of what they saw the day. Lots of  sightings went unreported for decades because it was not convenient to carry an old fashioned camera everywhere and cell phones were not yet invented with that convince. So I find it great that this eyewitness came forward to teach us about his/her sighting from that day. From what she describes, it sounds like the Foo Fighters UFOs from WWI and WW2 era. The UFOs curiosity of the moving car and it deliberately putting itself in the field of view of the car driver would indicate this. 
Scott C. Waring

Eyewitness states:
On a clear and sunny day, in broad daylight, on a very familiar road, while driving my car with some friends... What I can only describe as some kind of a "ball" of light (about the size of a large beachball) appeared, very suddenly, out of nowhere, directly in front of my car. In a bit of a panic, I asked my friends if they saw it too and they all definitely did. We were stunned and not sure what to do. It appeared to be floating/hovering/flying about 3 feet off the ground, and it was moving with us. There was no physical structure to it, as it appeared to be literally made of light. The light varied in color and was dynamic, not static. It was almost impossibly bright, like no other light source I've even seen, even though it was the middle of the day. It appeared about 30 feet in front of my car, and it seemed to be matching my speed. I was going about 40 mph at first, but I slowed down a little bit, not wanting to drive into it... but it seemed to slow down with me, remaining the same distance ahead of us. Then I sped up a little, and it did the same thing, matching my speed and remaining directly in front of my car. And then... it just disappeared. It was only there for a few seconds... maybe 10 or 15 seconds... before it vanished, just as it had appeared, into thin air. Also: There were definitely other cars on the road with me that day too, both behind me and in the lanes next to me and slightly behind me, but I have no idea if anyone other than my friends and I saw it. This happened in a pre-iphone/smartphone/cameraphone world, so none of us got any photos or video. (the image I uploaded was created by me, years later, using photoshop and a screenshot from google street-view of about where it happened.)