Root in my driveway

Last week I discovered a tree root (or is it a tree stump?) coming up out of the ground in my driveway. 

A few days later I found another tree root coming out of the ground near this root.  A root?  The trees in the yard aren't close to this spot.  Or is this an old tree stump trying to work its way out of the ground?  Time will tell.

I chopped the roots out of the ground.  I didn't want to drive over them.  Probably wouldn't be good for my tires.