Thank you good sir!
I could not come up with a better word for "grousers" that might be mistaken for a growler.
This from wiki:

Grousers function by trapping soil against the contact area of the track (in this case the slab). It is the shearing of the soil against itself that generates tractive force. The gross tractive effort, or soil thrust, of a vehicle (or sliding slab) may be calculated.

There are some alternatives that could be incorporated for ultimate stability in this driveway situation.
I believe the slab was not reinforced, thus I did not include doweling the slab into the wall with sliding sleeves, nor cutting the slab at a slight angle so that when it expands it is not forced up and over the cleat,, rather it is forced downward (and the soil would resist the slab from sinking) much like a dovetail.

Re-thinking the design (before construction).
1 - soil analysis
2 - design drive with some amount of "slight curves" and expansion joints at beginning and end of each curve, or
3 - design straight drive where it is divided into several 50' segments. Each segment would be a flat slab, with a "cleat, grabber or grouser" at the upper end of each slab.
Each upper slab could be doweled with sliding sleeves at each edge. The Cleats would need to have reinforcing steel bent like "L" shape the long segment going into the slab and the short down into the "cleat". the upper slab would include expansion joint material between that slab and cleat below.


Lastly think of a bridge abutment, or even a joist hangar and how it incorporates short curbs to keep the bridge deck in alignment or joist properly located.
The op drive is unconstrained and is pretty much floating around being pushed by thermal and loads. The wearing surface looks great; it's not breaking up, so feel the materials used are adequate.
This is an interesting situation and I hope to hear updates.

Do the proper expansion joints and I think that drive will out last us all. Cleat-less.