Oct 1984 at 8:15 am small translucent half dome shaped object

When I was 22 years old, I was driving to work through a suburban neighborhood around 8:15 am when I saw a gliding translucent half dome shaped object.  It is important to note that the object was not floating in the air; it was actually gliding on top of the road.  I remember looking at it and wondering if I was seeing things.  
I stopped the car and just watched it glide slowly across the road in front of me.  It was only about 15 feet away from me.  It looked to be maybe 4 feet wide by 3 feet high from the angle I could view it.  It was translucent, but not transparent, sort of like aurora borealis glass, but you couldn’t see through it.  
It was perfectly symmetrical and glided very slowly without bumps or stops or starts. 
I stayed in the car and I looked around to see if anyone else was witnessing what I was, but no one else was nearby.  
The material was so different, and the way the object moved, I have never seen anything else like it.
Witness indicates that the date of the event is approximate.  PD