The thickness of asphalt on a new driveway or parking lot will depend on several factors, including the expected traffic volume, climate conditions, and the underlying soil composition. In general, here are some guidelines for the thickness of asphalt:

1. For light-duty residential driveways, the asphalt thickness should be at least 2-3 inches.
2. For heavier-duty commercial or industrial applications, the asphalt thickness should be at least 4-6 inches, or more depending on the expected traffic load.
3. In areas with harsh winter climates or where there are frequent freeze-thaw cycles, the asphalt should be thicker to prevent cracking and damage.

It’s important to note that these are just general guidelines, and the thickness of the asphalt for your specific project should be determined by a professional engineer or contractor. They will take into account factors such as soil conditions, drainage, and local regulations to determine the appropriate thickness for your driveway or parking lot.