A few things to remember when having asphalt done. The mixture of what is used to create it is done at the plant, specified by the person buying it. There are ways to make it stronger, but that costs more money. One of my clients runs the local plant, and they had a parking lot fail. The owner of that parking lot was not happy, and during the course of the lawsuit, it came out that the contractor did not order the specified mixture of asphalt. He went with driveway grade asphalt instead of parking lot grade. I'm paraphrasing a conversation, and my terms are not accurate, just how I remember them. The contractor then tried to blame the plant for mixing it wrong and that they should provide the new asphalt needed to do the parking lot for free. In the end, the plant spent tons of money defending itself and the contractor ended up tearing out the parking lot and doing it over again, paying for all of it.
If you are going to do asphalt, be sure to know how thick it needs to be in your area, how wide it needs to be. You never want to be driving at the edge of it, so there needs to be a certain amount outside the tires. And of course, you need to know what your options are in the mixture of it, and what you want to pay for. Lastly, you have to make sure you actually get what you order!!!!
Having said all that, road base gravel, called different things in different places only fails when it's too thin. Sadly, this usually happens because some guys just love regrading it and dragging their box blade over it several times a year. This is the worse thing in the world for a gravel driveway. Once compacted, it should NEVER be touched again. If you get a pothole, you dig out the pothole, fill it, compact it and then leave it ALONE!!!
No matter what you think you can do asphalt for or concrete for, gravel is going to be a small fraction of those costs. Making the gravel twice as thick as you need it is still going to be a fraction of the cost of having a paved driveway. Do you really need a paved driveway or would it be more cost effective to put int he very best gravel driveway possible for a lot less money?
Here in East Texas, 4 inches of crushed limestone from 3 to fines is what we use. I went with 6 inches ten years ago and have only had a few potholes that have developed. I built up my dirt base several inches to bring it above the surrounding grade, so water is never an issue. Then after compacting the soil, I spread the rock. Water it down and compacted it, and nothing else in ten years.