Home › Blog › Reduce diesel consumption on a construction fleet: 8 measurable levers

2026-11-04 · 8 min read · GeoChantier team · Canalytics Group

Reduce diesel consumption on a construction fleet: 8 measurable levers

Key takeaways

Three indicators are enough to manage diesel: litres per engine hour, idle percentage and litres per m³ moved.
Idling can take as much as 40 to 60% of engine time according to Volvo CE, and a 5-minute auto shutdown is the fastest win.
One extra point of rolling resistance cuts haul truck speed by 10 to 26%, which is why haul road upkeep pays.
Too many trucks per excavator builds a loading queue, which means paid idling with no production.
Savings in MAD equal (L/m³ before − L/m³ after) × m³ produced × price per litre, on a comparable scope.

To reduce diesel consumption on an earthmoving fleet, start by measuring three indicators per machine: litres per engine hour (L/h), idle percentage and litres per m³ moved. The fastest gains usually come from idling, haul road condition, payload and excavator-truck matching. Each lever can then be priced in MAD from telematics data, as long as production is comparable.

Which indicators should you track to manage fleet diesel?

Three ratios cover most of it:

L/h per engine hour, per machine and per day: raw consumption, useful to spot a machine that drifts.
Idle percentage = idle hours ÷ engine hours.
L/m³ (or L/t, L per linear metre laid) = litres burned ÷ volume produced on the work package. This is the only ratio that separates a real saving from a simple drop in activity.

The ISO 15143-3 standard (AEMP 2.0) harmonizes manufacturer data: location, operating hours, total fuel used and fuel used in the last 24 hours, with optional fields such as cumulative idle hours and average engine load factor (AutoPi, AEMP 2.0 summary). A mixed Cat, Komatsu and Volvo fleet can therefore be read on a common basis. GeoChantier is being designed to pull this data (or data from a GPS unit) and derive an hourly cost per machine, per work package and per day, in MAD or CAD. The platform is under development.

How much does idling cost, and what engine-off policy works?

This is the best-documented lever. Volvo CE reports that machines can idle for as much as 40 to 60% of their operating time (Volvo CE). Caterpillar says idle time of 40 to 50% of running time is not unusual (Caterpillar), and Komatsu cites an average of nearly 40% (Komatsu). According to Caterpillar, most construction equipment burns about one gallon, or 3.8 L, per hour at idle (Caterpillar via ForConstructionPros), the same order of magnitude Argonne reports for a big truck (Argonne National Laboratory).

A simple engine-off policy drawn from manufacturer guidance:

limit warm-up to 3 to 5 minutes at the start of a shift, and cool-down to 2 minutes before shutdown;
shut off trucks that wait more than 5 minutes to load or unload (Caterpillar);
turn on auto shutdown: 5 minutes is the minimum delay on most Komatsu Tier 4 Final machines, and Volvo CE shuts down after 5 minutes of inactivity with a warning at 4 minutes.

How to measure it: idle hours per machine, per operator and per geofence (loading area, site camp, workshop). Idling concentrated in the loading area points to a queue; treat it with the matching approach described below.

How does haul road condition drive up consumption?

Rolling resistance is expressed as a percentage of gross weight and adds to grade. Caterpillar's haul road presentation uses 1.5% for a hard, well-maintained road, 4% for 25 mm of tire penetration and 8% for 100 mm (Caterpillar, Haul Road Design and Management). The same document states that a 5-point increase can cut production by up to 10% and raise production costs by 35%, as trucks travel slower in lower gears. Roger Thompson (Curtin University) calculates that one extra point of rolling resistance reduces truck speed by 10 to 13% on a ramp and by 18 to 26% on the flat (Thompson, 2009).

Grade matters too: an SAE study of CAT 773D, Komatsu HD465-7 and Volvo A40E trucks measured loaded fuel consumption rising 13 to 24% per additional point of grade, and recommends a maximum grade of 8% (SAE 2022-01-5030).

How to measure it: average speed and L/h of loaded trucks per haul road segment (geofences), before and after a grader pass or watering.

Payload: why aim for the target and no higher?

Caterpillar recommends the 10/10/20 policy: the average payload stays at or below target, no more than 10% of loads exceed 110% of target, and none exceed 120% (Caterpillar, scale studies). Overloading increases fuel burn and wears tires and components; underloading pays for incomplete cycles. On-board weighing systems typically measure within 1% of gross vehicle weight (ForConstructionPros).

How to measure it: litres per tonne or per m³ hauled, and the payload distribution per truck and per loader.

Should you cap haul truck speed?

Driving fast toward a busy excavator only lengthens the queue. A TU Delft thesis used simulation (HaulSim, Cat 793 trucks) to adjust truck speeds and reduce loading queues at constant production; it found 27 to 32% lower fuel consumption across scenarios, with the author cautioning that the figures should be read carefully (Vis, TU Delft, 2023). Engine speed matters too: at a mine running 72 trucks, Komatsu found that fuel use nearly doubles between 1,500 and 1,900 rpm while dumping, and that 30% of dumps ran at excessive engine speed (Komatsu case study).

How to measure it: peak and average speed per segment, engine speed during dumping, waiting time at the excavator.

How does excavator-truck matching cut diesel?

The match factor compares truck hauling capacity with excavator loading capacity. At the Djebel Onk phosphate mine in Algeria, the queuing model by Debbouz et al. shows average waiting time at the loader rising from 3 minutes with 7 trucks to almost 11 minutes with 12 trucks, while truck utilization falls to 67.5% (Debbouz et al., 2024). Every minute in the queue is paid idling.

The reasoning is covered in our article on the construction digital twin for haul cycles.

Operator training and coaching

Caterpillar estimates that a skilled operator can use 10 to 12% less fuel per day than an unskilled one (Caterpillar). Skanska reported a 5% annual fuel saving after 50 operators completed Volvo training (The Construction Index). Volvo CE claims up to 50% for its Eco Operator training: treat that as a marketing ceiling and verify it on your own data.

How to measure it: L/h and idle time per operator, on comparable machines and tasks, over four weeks before and after.

Maintenance: tires, filters and tuning

According to the EPA SmartWay program, truck tires underinflated by 10 psi can reduce fuel economy by 0.5 to 1%, and a tire can lose up to 2 psi per month (EPA SmartWay). Volvo CE recommends checking pressures at the start of every shift and servicing air filters, since clogged filters hurt consumption and performance. Natural Resources Canada notes that a poorly tuned engine can use up to 15% more energy at idle (NRCan).

How to measure it: deviation of a machine's L/h from its own 30-day average on similar work. A sustained increase triggers an inspection.

Right-size the fleet

An oversized machine burns diesel for power it does not use. Komatsu describes a study where the customer moved to smaller equipment and used the savings to buy a second WA380 wheel loader (Komatsu). Volvo CE stresses that properly sizing articulated haulers, excavators and wheel loaders drives both output and fuel use.

How to measure it: average engine load factor, engine hours against productive hours, m³/h per machine.

Summary table of levers

Lever	Indicator to track	Published benchmark
Idling	Idle %, L/h at idle	Up to 40 to 60% of engine time (Volvo CE); shut off at 5 min
Haul roads	Loaded speed and L/h per segment	+1 point of resistance: −10 to −26% speed (Thompson)
Payload	L/t, payload distribution	10/10/20 policy (Caterpillar)
Speed	Speed per segment, wait at excavator	−27 to −32% in simulation (TU Delft)
Matching	Loading queue, excavator utilization	Wait of 3 to 11 min from 7 to 12 trucks (Djebel Onk)
Operators	L/h and idle per operator	10 to 12% gap (Caterpillar)
Maintenance	30-day L/h drift	−10 psi: −0.5 to −1% (EPA)
Right-sizing	Load factor, m³/h	Komatsu case example

How do you calculate savings in MAD?

The basic formula: savings (MAD) = (L/m³ before − L/m³ after) × m³ produced over the period × diesel price (MAD/L).

An example, using assumptions you should replace with your own figures: one excavator and five trucks, 10 engine hours per day, 22 days per month, 40% measured idle, 3.8 L/h at idle and diesel assumed at 12 MAD/L. Bringing idle down to 25% removes 6 × 10 × 0.15 = 9 idle hours per day, which is 34.2 L per day, 752 L per month and about 9,030 MAD per month.

On the production side: 1,200 L for 2,000 m³ gives 0.6 L/m³, or 7.2 MAD/m³ in diesel. Saving 0.05 L/m³ on a 40,000 m³ work package is 2,000 L, or 24,000 MAD.

Three precautions: compare periods with similar material and haul distance, measure over at least two to four weeks, and use the idle L/h actually measured on your machines rather than a generic value.

From measurement to action

GeoChantier, published by Canalytics Group, is under development. It is designed to offer costed recommendations: reassign a machine, shorten a loading queue, cut idling. To join the pilot programme, tell us about your fleet. For a question about your fleet in Morocco or Canada: contact@canalytics-group.com.

Frequently asked questions

How much fuel does construction equipment burn at idle?

Caterpillar states that most construction equipment burns an average of about one gallon, close to 3.8 litres, per hour at idle. The real figure depends on engine size, accessories and air conditioning. The most reliable approach is to measure it on your own machines by dividing the fuel used during idle hours by those hours, using telematics data.

How long should a machine idle before the engine is shut off?

Manufacturers converge on 5 minutes. Caterpillar recommends shutting off trucks that wait more than 5 minutes to load or unload, Komatsu sets 5 minutes as the minimum auto idle shutdown delay on most Tier 4 Final machines, and Volvo shuts down after 5 minutes of inactivity. Keep 3 to 5 minutes of warm-up and 2 minutes of cool-down.

How do you calculate fuel consumption in litres per m³?

Add up the litres burned by every machine assigned to a work package over a period, then divide by the volume actually moved on that package, measured by haul cycle counts, payload weighing or survey. For example, 1,200 L for 2,000 m³ gives 0.6 L/m³. Always compare periods with similar material and haul distance.

Does operator training really reduce fuel consumption?

Yes, by measurable amounts. Caterpillar estimates that a skilled operator uses 10 to 12% less fuel per day than an unskilled one, and Skanska reported a 5% annual fuel saving after 50 operators completed Volvo training. To check the effect on your fleet, compare litres per hour and idle time per operator over four weeks before and after training.

How many trucks should be assigned to one excavator to save fuel?

Aim for a match factor close to 1, where hauling capacity equals loading capacity. Beyond that, trucks wait with engines running. At the Djebel Onk mine in Algeria, average waiting time at the loader rose from about 3 minutes with 7 trucks to almost 11 minutes with 12 trucks. Measure the actual queue by geofence before adding a truck.

Sources

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