15 Fleet Fuel Numbers Every Small Service Business Should Know (2026)

Fuel is the second-biggest cost in most service fleets after payroll — and the only major cost that changes price every single week. Yet most owners couldn't say what idling costs them per hour, what speeding adds per gallon, or what share of every operating dollar goes into the tank.

Here are 15 numbers that answer those questions, pulled from the U.S. Energy Information Administration, Argonne National Laboratory, the Department of Energy, and the American Transportation Research Institute — with the math worked out for a small service fleet. Every stat links to its source, so you can cite these in your own budgeting (or your next argument about the thermostat setting on the truck AC).

Spytec GPS is a self-serve GPS fleet tracking platform built for small and mid-size fleets, with free hardware on every plan, no contracts, and transparent pricing from $8.95/vehicle/month (annual). Fuel level monitoring and idle alerts are included on every plan — no feature tiers.

What fuel costs right now (July 2026)

1. Regular gasoline averages $3.86 per gallon nationally. Per the EIA's weekly Gasoline and Diesel Fuel Update (July 13, 2026), the U.S. average for regular is $3.855 — up 72.5 cents from a year ago.

2. On-highway diesel averages $4.80 per gallon — up $1.04 in a year. Same EIA release: $4.796 national average, a 27% year-over-year increase. If your fleet runs diesel vans or trucks and your budget still assumes last summer's prices, it's roughly a quarter short.

3. Where you operate can swing fuel cost by 50%. EIA's regional data shows regular gas at $3.42 on the Gulf Coast versus $5.20 in California. A ten-van fleet burning 500 gallons a week pays about $890/week more in Sacramento than in Houston for the same routes.

4. Fuel is roughly 48 cents of every mile a commercial truck drives. The American Transportation Research Institute's operational cost data put fuel at 48.1 cents per mile in 2024 — about 21% of the total $2.26/mile cost of operation, second only to driver wages.

What idling costs (the silent one)

5. U.S. vehicles burn more than 6 billion gallons of fuel a year going nowhere. Argonne National Laboratory's idle-reduction research puts the cost at over $20 billion annually — fuel consumed at zero miles per gallon.

6. Roughly half of that waste comes from commercial vehicles. Also Argonne: medium- and heavy-duty commercial vehicles account for about half of all idling fuel loss. This is a fleet problem more than a commuter problem.

7. A diesel work truck burns about 0.8 gallons per hour at idle. That's the Department of Energy/Argonne figure for commercial diesel vehicles. At July's $4.80 diesel, that's about $3.84 per hour per truck, per hour of idle.

8. A gas-powered van burns roughly 0.2–0.4 gallons per hour at idle. Argonne's aggregated data for gasoline engines (small sedans at the low end, larger V8s at the top). At $3.86 gas, call it $0.77–$1.54 per hour.

9. One hour of daily idle costs a service fleet $960 per diesel truck per year. Our math from the two numbers above: 0.8 gal/hr × $4.80 × 250 working days. Across a ten-truck fleet, an hour a day of unnecessary idling — lunch breaks with the AC running, warm-ups, waiting at the supply house — is roughly $9,600 a year. For how to actually find it, see our guide to spotting fleet fuel theft and waste.

What driving behavior costs

10. Aggressive driving cuts fuel economy by 15–30% at highway speeds. Per the DOE's fueleconomy.gov: speeding, rapid acceleration, and hard braking lower gas mileage by roughly 15%–30% on the highway and 10%–40% in stop-and-go traffic. For a van averaging $500/month in fuel, the difference between your calmest driver and your most aggressive one can be north of $100/month.

11. Every 5 mph over 50 is like paying an extra $0.32 per gallon. Also fueleconomy.gov: fuel economy drops rapidly above 50 mph. A tech running 75 in a 60 isn't just a liability risk — he's voluntarily paying a premium at every fill-up.

12. Underinflated tires cost 0.2% of fuel economy per PSI, per tire. DOE data: a van running 8 PSI low across four tires gives up about 1.6% of its fuel economy — invisible on any single tank, real across a fleet-year.

What the tank never explains

13. Rest-period idling alone costs U.S. trucking up to 1 billion gallons and $3 billion a year. DOE/Argonne's figure for long-duration rest idling — an enterprise trucking number, but it shows how fast stationary engine-hours compound into real money.

14. Fleets actively managing fuel with tracking data report 10–25% consumption reductions. This one is industry-reported rather than government-measured, so treat it as a range, not a promise — but it's consistent across telematics providers, and the mechanisms are the numbers above: idle alerts, speed alerts, and route data attack stats 7–12 directly.

15. The math on tracking pays for itself at one hour of idle per week. Our arithmetic, transparent: Spytec costs $8.95/vehicle/month (annual plan). One avoided hour of diesel idle per week saves ~$16.60/month per truck (stat 7). You don't need the 25% best case — recovering four hours of idle a month covers the subscription, and everything past that is margin. Where the money actually leaks per jobsite, our fleet job costing guide shows how to trace it.

The bottom line

You can't negotiate the price at the pump — stat 2 says it moved a dollar in a year without asking you. What you control is gallons: idle hours (stats 5–9), speed (stats 10–11), tire pressure (stat 12), and knowing which truck is burning more than its routes justify. Every one of those is measurable, and none of them show up on a fuel card statement.

For the broader picture beyond fuel, see our fleet management statistics for 2026.

FAQ

How much does idling cost a fleet per hour?

A commercial diesel vehicle burns about 0.8 gallons per hour at idle (Argonne National Laboratory), which at July 2026's $4.80/gallon national diesel average costs about $3.84 per hour. Gasoline vans burn roughly 0.2–0.4 gallons per hour at idle, or about $0.77–$1.54 per hour at $3.86/gallon gas.

What percentage of fleet operating costs is fuel?

Fuel accounted for roughly 21% of total per-mile operating costs for commercial trucks in 2024 — 48.1 cents of a $2.26/mile total, per the American Transportation Research Institute. For small service fleets, fuel is typically the second-largest expense after payroll.

How much does speeding increase fuel costs?

According to the U.S. Department of Energy, fuel economy drops rapidly above 50 mph, and every 5 mph over 50 is equivalent to paying about $0.32 more per gallon. Aggressive driving overall (speeding, rapid acceleration, hard braking) reduces fuel economy 15–30% at highway speeds.

How much can GPS tracking reduce fleet fuel costs?

Fleets that actively manage fuel using tracking data report consumption reductions of 10–25%, primarily through idle alerts, speed monitoring, and route data. The mechanisms are well documented in government data even though the savings ranges are industry-reported. At Spytec GPS's $8.95/vehicle/month annual rate, recovering about four hours of diesel idle per month covers the cost of the subscription.

What is the average price of diesel in 2026?

As of the EIA's July 13, 2026 weekly update, on-highway diesel averages $4.80 per gallon nationally — up $1.04 (27%) from a year earlier. Regular gasoline averages $3.86 per gallon, up 72 cents year over year. Prices vary widely by region, from roughly $3.42 (Gulf Coast gas) to $5.20 (California gas).