Large blueish green disc shaped craft stopped and hovered

My wife was driving and we were on our way to 7-11 around midnight.
The sky was clear and we were driving east. I saw it from a distance, like a tiny pinpoint of light that suddenly was coming towards us and 1/4 of a second later it instantly stopped just ahead of us and to the left.
It hovered there in silence as my wife slowed the car to a stop. There wasn't another car in sight, we both just sat there and stared at it.
It was about 8-9 stories high and almost that wide. Probably 6-7 stories high if it turned sideways. It was disc shaped, totally smooth all over. It looked like the entire disc was a dull blueish green color like a dull led light. I noticed it was perfectly round but the top portion was a little larger than the bottom section.
We both stared at it for about 15 seconds and both of us had goosebumps.
Then suddenly we both at the exact same time turned around and looked at the back seat.  Nothing was there but I had the strangest feeling there was someone there.  I immediately asked my wife why she turned around and looked at the back seat and she said the she had the same feeling that I did, that someone was there.  Then we started laughing and we looked back up at the craft and stared at it a few more seconds when it suddenly took off in a flash towards the south.  It was out of sight within another 1/4 second.  I've never seen anything move even close to that speed.
When I think about all the stories I've heard about ufo's I think the one we saw was one of the coolest and for years I'd never heard or read another story that described a similar craft until the one from the airport in chicago a couple years ago. That one sounded similar even though it was in the daylight and was silver in color.
Witness indicates that date of the sighting is approximate.  PD