Asphalt Thickness Guide — Driveways, Parking Lots & Roads
The right thickness is the difference between a pavement that lasts 20 years and one that needs repair in five. This guide follows AASHTO and common US state DOT practice.
Residential Driveways
| Use | Asphalt | Aggregate Base |
|---|---|---|
| Cars / SUVs | 2 in compacted HMA | 4–6 in |
| Pickup / occasional RV | 2.5–3 in | 6 in |
| Heavy vehicles / long driveway | 3–4 in | 8 in |
Commercial Parking Lots
- Light duty: 1.5 in surface + 2 in binder = 3.5 in over 6 in base.
- Medium duty: 2 in surface + 3 in binder = 5 in over 8 in base.
- Heavy duty: 2 in surface + 4 in binder = 6 in over 10 in base.
Roads
- Local / residential street: 2–3 in HMA over 6–8 in aggregate.
- Collector road: 3–4 in HMA over 8–10 in aggregate.
- State/US highway: 4–6 in HMA over engineered base.
Golden Rule
Never economize on the base. Cutting asphalt depth by 0.5 in saves ~5% in material; cutting the aggregate base by 2 in can cut pavement life in half.