OT but so what?

Is there a spring there? Is the driveway ditched, or otherwise close to good drainage? Mebbe that much effort could be better spent putting tile under the thing into a drain line to keep out the water that's making it soft?

I'm very much guessing here -- road building is not my forte.

I would dig out the area to below frost level. Then add some landscape fabric and fill to within a foot of the surface with 2". Now for the last layer you will want something like crush and run, then mix some portland cement in with that. Mix it well and level it, then wet it down very well.

If you have excessive silt content then its best to first put in a lift of fairly large aggregate with no fines, sometimes called large drain rock..as they settle, the space between them will become occupied with the silt from underneath.

On top of that, you want an intermediate layer, down here we usually use what's often referred to as "rejects" or "track rock"...it's typically

1-1/4 minus which means it also has fines.

Finally, you want crushed rock, for smooth ride I suggest 5/8 minus, an inch or more thick.

Potholes form because the road surface is flat, so make sure you have a crown instead, such that water will run off, keeping any fines or clay from becoming plastic....

Also, where the road is built along a hill side, it's imperative to have a definite ditch on the uphill side, in order to keep water from forming a gullue that runs down the center of the roadway, and if the road runs through a "cut" (hillside extending upward on BOTH sides), then there must be a ditch on BOTH sides, otherwise you'll have a freaking lake any time there's a hard rain.

Best way to look at it is, take dirt from where you want the water to go, and place it where you don;t want the water to go, then top it off with progressively finer aggregate, finishing it off with a crown in the center--much easier said than done though, especially if you're in an area where it rains quite a bit during the winter months.

I prefer these materials in this order:

1 - Shale = stays flattest, sinks in less than gravel (disclaimer: I haven't worked with it yet, except on a repair basis) 2 - DG (decomposed granite) = smoothest of the 3 3 - 3/4-minus gravel = best for hilly drives with much rain.

We don't get much snow here so I have no idea how any of those three react with snow and ice on top. Your best bet is to talk to the sales critters at the trucking places which offer the materials. You may have to talk to one from each type of material. All 3 are separate companies here in GP. All are about $150-200 per 10yd dump, delivered. Less in larger quantities, but the pony trailers aren't as good at smoothly dumping the rock on the ground so it doesn't have to be messed with by the owner.