Go to Cornell University website and and read thru their rural roads program.
https://cceschoharie-otsego.org/emergency-preparedness/cornell-local-roads-program
I strongly suggest you use a filter fabric over the existing soil. This is standard practice for reducing the problem of the subsoil 'mixing' with your driveway aggregate and 'softening' the driveway surface. It should also allow you to reduce the amount of road base material you will need. (Tip: Old carpet can also fill this need for a filter fabric membrane.)
Crown the subsoil for water drainage, provide swales or ditches on both side to drain away surface water, lay down your soil filter fabric, apply road base (mix of #2, #1, and fines of crushed rock) that is unevenly spread at 3 to 4 inches deep, wet down to help the fines fill the gaps between the #2 and #1 rocks, then compact the road base (or let it dry for a couple weeks without driving on it) and this will give you a hard flat surface that will actually shed a great deal of any water (rain or snow) that falls on it.
