The thickness of an asphalt parking lot can vary depending on several factors, including the expected traffic load, soil conditions, climate, and local building codes. However, a typical recommendation for the thickness of asphalt pavement in a parking lot is around 2 to 3 inches for light to moderate traffic loads, and up to 4 to 6 inches for heavier traffic loads or commercial applications. Additionally, a stable base layer of crushed stone or gravel is usually installed underneath the asphalt layer to provide structural support and prevent cracking.