If your really looking to spend $30-50k on a driveway; it worth the time/expense/effort to have a contract, with a spec, material call outs, and some Geotechnical testing.
For a residential, asphalt driveway, in my part of the world (that affects the terms used) I would spec, subgrade to be stripped of organic materisl/top soil, proof rolled, and shaped to the finished shape, then 6" of limerock, LBR100, from an approved pit, compacted to 98% density, primed with asphalt emulsion prime (I like Special MS), and than, 165#/sy of Superpave Sp-12.5, traffic level-b, rolled with a min 4 ton roller.
The density testing would require either a pit proctor or a proctor and LBR pulled (cost you about $500 and 3 days wait), and then a density taken every 500 lf at a random location (that'd gonna be about $120 per test, with a 3 test min, or about $360). Yes, you dropped $900 in testing, but you have a leg to stand on.
If your contractor doesn't understand any of the terms (or he'll, if he starts talking about square feet) I'd run away. The terms vary area to area, so, down load a copy of your local county/city/state DOT standards, or local Land Developemnt Code; work if building a home, have your EOR write the spec for the driveway. Just understand your driveway is not a road, and a road spec like (tyoical FDOT) 12" stabalized subgrade LBR40; 10" limerock, LRB100; 2.5" SP-12.5 and 1.5" FC-12.5; traffic level C; is not needed for a home drive; that's designed to carry 10,000 plus trips per day, for 7-14 years.
Most guys doing small work for homeowners are a iffy lot at best.