Soccer ball sized orange glowing sphere bounced from one side of the road to the other.

In July of 1976 I was traveling East on Cemetary Road on Vashon Island. Time was about 1430 hrs. Weather was clear. 
Fifty yards ahead of me a glowing ball came out of the woods on the South side of the road, slowly bounced twice on the road, and went into the woods on the North side of Cemetary Road. Size was about the same as a soccer ball. Color was glowing orange. About the same color as a barracade light. 
The glow seemed to come from internal sources. The sphere seemed to be traveling in slow motion. There was no sound, or any other external emission from the ball. There was no siesmic activity at the time. I considered ball lightning, but the size and weather does not support that theory. 
I am a retired Seattle Fire Fighter, and have been a pilot for over forty years. I am also an expert in aircraft identification. All I can say about the glowing ball is, I know what it wasn't.