How the calculation works

1. Modulus: E (MPa) = CBR × k; E (Pa) = E (MPa) × 1,000,000.
2. Deflection: δ = wheel load ÷ (π × contact radius × E in Pa).
3. Rolling resistance: RR = α × δ + β. Multiply by 100 to show a percentage.
4. Tractive force: F = RR × vehicle mass × gravity.
5. Journey energy: MJ = F × journey distance ÷ 1,000,000.
6. Fuel equivalent: liters = MJ ÷ diesel energy density. Journey cost = liters × diesel price.
7. Calculate loaded and empty journeys separately. Empty mass and wheel load use their respective factors.
8. Annual cycles = cycles per truck per day × fleet size × operating days.
9. Annual saving = (existing cycle cost − improved cycle cost) × annual cycles.

What this estimate includes

Only the modeled energy cost attributed to rolling resistance on the selected journey segments. Both road scenarios use the same operating schedule, fuel price, and truck settings. Each daily cycle includes one loaded trip and, when selected, one empty return.

What it does not include

Engine or drivetrain efficiency, gradient, aerodynamic drag, acceleration, idling, auxiliaries, speed or cycle-time changes. The spreadsheet divides mechanical energy directly by diesel energy content; its liters are therefore fuel-energy equivalents, not a prediction of actual fuel consumption. No efficiency multiplier has been added.

Water spraying, tire wear, maintenance, productivity, emissions, treatment cost, payback, and net return on investment are not quantified by the source formulas and are excluded. The workbook’s narrative tire-saving range is not added to the result.

Workbook audit decisions

• All three visible sheets—Calculator, README, and Haul Truck Library—and the hidden Formula_Audit sheet were reviewed.
• The headline uses the complete cycle (Calculator rows 104–121), rather than the earlier loaded-only headline cards.
• All nine truck presets are copied from the supplied library. These are workbook reference values, not independently verified manufacturer specifications.
• CBR is not capped at 100: the workbook itself uses an improved CBR of 200, despite its conflicting validation rule.
• Tire size and pressure are reference information; they do not independently feed the formulas. Contact radius is not recalculated from pressure.
• Negative savings remain visible as a modeled cost increase. Zero trips, distance, or fuel price correctly produce zero applicable costs.
• The saved source uses k = 15 for the improved scenario, despite a note mentioning 20 for treated soil. The calculator preserves 15.
• The source print area ends at row 76, so the return-leg and complete-cycle sections below it can be missed in a printed copy.

Source: Rolling Resistance Reduction - Cost Savings Version 1.01.xlsx. This calculator reproduces its empirical model; site calibration and review are needed before using estimates in a business case. Source workbook copyright notice retained: © 18 June 2026.