Based upon various cities, counties and MDOT specs,and on average loads and soils
| Sub-base | 6 inches | 21-AA limestone | 
| Base | 2.5" | 20-A asphalt | 
| - | 2.5" | 20-AA asphalt | 
| - | 2.5" | 20-A recycled asphalt | 
| Top | 1.5" | 36-A asphalt | 
For maximum life (approximately 15-20 years) and reduced repairs. "Reduced thickness usually means reduced life."