Poor haul road design is a primary driver of operational costs in mining and heavy industry. When a road is under-designed or poorly maintained, it creates a “hidden tax” on every cycle, primarily through increased rolling resistance and mechanical stress [1].
Effect on Fuel Consumption
Fuel is often the single largest variable cost in hauling. Poor design increases consumption in three main ways:
- Increased rolling resistance (RR): if the road surface is soft, poorly compacted, or covered in loose material, the tires “sink” slightly. The engine must work significantly harder to overcome this resistance [2].
- The 1% Rule: In many mining environments, every 1% increase in rolling resistance can lead to a 2–3% increase in fuel consumption.
- Sub-optimal gradients: roads that are too steep or have inconsistent slopes (constant gear hunting) force engines to run at high RPMs in low gears. A 1% increase in ramp grade can lead to fuel savings of up to 1.6% if optimized.
- Poor geometric layout: sharp curves and steep “stop-start” intersections break the vehicle’s momentum. Every time a 400-ton truck has to brake and re-accelerate, it consumes a massive burst of fuel that could have been avoided with better banked (super-elevated) curves and gradual gradients.
Effect on equipment maintenance
A poorly designed road acts like a “vibration machine” that systematically breaks down vehicle components:
- Tire Life: Tires are the biggest maintenance expense after fuel. Poor roads cause:
- Cuts and bursts: from loose “scattered” rocks that haven’t been graded away.
- Overheating: high rolling resistance causes tire sidewalls to flex more, generating heat that leads to premature failure. Poorly maintained roads can reduce tire life by 30% or more.
- Suspension and frame stress: potholes, ruts, and “corrugation” (washboarding) transmit high-impact shocks directly into the chassis. This leads to fatigue cracking in the frame and frequent replacement of struts and bushings.
- Drivetrain strain: inconsistent grades and soft surfaces put constant, uneven torque on the transmission and differentials. This results in “gear hunting,” which overheats the transmission fluid and accelerates wear on the gear teeth and torque converters.
- Braking systems: roads without proper runaway ramps or those with excessively steep downhill sections cause brake overheating and “fade,” requiring more frequent replacement of brake pads and cooling systems.
Reference
[1] O. Gölbaşı and E. Kina, “Haul truck fuel consumption modeling under random operating conditions: A case study,” Transportation Research Part D: Transport and Environment, vol. 102, p. 103135, Jan. 2022, doi: 10.1016/j.trd.2021.103135.
[2] DFXadmin, “The importance of haul road design,” Tyre Doctor. Accessed: Jan. 12, 2026. [Online]. Available: https://tyredoctor.com.au/news-and-video/articles/the-importance-of-haul-road-design/
