Use this tool to calculate the ESAL of a single truck, lorry, or construction vehicle. Simply enter the number of front and rear axles, total axle loads (in tonnes), and number of passes. The calculator shows you the per-axle ESAL contribution, total ESAL per pass, and overall ESAL for the specified number of trips. A diagram of the vehicle updates dynamically to illustrate axle placement and load distribution.
How to Use the Tool
- Enter the number of front axles and their combined load.
- Enter the number of rear axles and their combined load.
- Input the number of passes (trips) the vehicle makes.
- Click Calculate & Draw to generate:
- ESAL per pass
- ESAL breakdown by axle
- Total ESAL for all passes
- A vehicle diagram with axle loads labeled
ESAL Calculator & Vehicle Diagram
Enter vehicle axle configuration and loads. The diagram stretches the trailer to accommodate rear axles and labels each axle with its load and ESAL contribution.
How the ESAL Calculator Works
The ESAL (Equivalent Single Axle Load) method converts any axle load into an equivalent number of passes of a standard axle. The standard reference axle is:
- 80 kN (≈ 8.16 tonnes), single axle, dual wheel.
The formula used is:
ESAL per axle = (Axle Load ÷ 8.16)^4
- Loads are evenly distributed across the entered number of axles.
- The calculator computes ESALs for each axle, sums them for a single vehicle pass, and multiplies by the number of passes.
- If more than 12 rear axles are entered, the tool still calculates ESALs correctly, but the diagram caps the display to 12 axles for clarity.
Example ESAL Calculation
Suppose a 3-axle rigid truck has:
- 1 front axle carrying 7.5 tonnes
- 2 rear axles carrying 9.5 tonnes each
Then:
- Front axle ESAL = (7.5 ÷ 8.16)^4 = 0.714
- Each rear axle ESAL = (9.5 ÷ 8.16)^4 = 1.837
- Total ESAL per pass = 0.714 + 1.837 + 1.837 = 4.388
If the truck makes 18 passes, the total ESAL = 18 × 4.388 = 79.0
Why ESALs Are Important
- ESALs provide a standardized way to measure pavement wear from different vehicles.
- Road authorities and engineers use ESALs to design pavements that can withstand expected traffic loads.
- For developers, contractors, and planners, ESAL analysis helps demonstrate compliance with municipal requirements and avoids costly disputes about construction traffic impacts.
Single Vehicle vs. Traffic Load Estimators
This calculator is designed for individual vehicles. If you need to estimate ESALs for an entire construction project or road segment with mixed traffic, use our General ESAL Traffic Load Estimator
Need a Full Traffic Impact Assessment?
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